| 1 | |
| 2 | |
| 3 | * linux/kernel/fork.c
|
| 4 | *
|
| 5 | * Copyright (C) 1991, 1992 Linus Torvalds
|
| 6 |
|
| 7 |
|
| 8 | |
| 9 | * 'fork.c' contains the help-routines for the 'fork' system call
|
| 10 | * (see also entry.S and others).
|
| 11 | * Fork is rather simple, once you get the hang of it, but the memory
|
| 12 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
|
| 13 |
|
| 14 |
|
| 15 | #include <linux/anon_inodes.h>
|
| 16 | #include <linux/slab.h>
|
| 17 | #include <linux/sched/autogroup.h>
|
| 18 | #include <linux/sched/mm.h>
|
| 19 | #include <linux/sched/coredump.h>
|
| 20 | #include <linux/sched/user.h>
|
| 21 | #include <linux/sched/numa_balancing.h>
|
| 22 | #include <linux/sched/stat.h>
|
| 23 | #include <linux/sched/task.h>
|
| 24 | #include <linux/sched/task_stack.h>
|
| 25 | #include <linux/sched/cputime.h>
|
| 26 | #include <linux/sched/ext.h>
|
| 27 | #include <linux/seq_file.h>
|
| 28 | #include <linux/rtmutex.h>
|
| 29 | #include <linux/init.h>
|
| 30 | #include <linux/unistd.h>
|
| 31 | #include <linux/module.h>
|
| 32 | #include <linux/vmalloc.h>
|
| 33 | #include <linux/completion.h>
|
| 34 | #include <linux/personality.h>
|
| 35 | #include <linux/mempolicy.h>
|
| 36 | #include <linux/sem.h>
|
| 37 | #include <linux/file.h>
|
| 38 | #include <linux/fdtable.h>
|
| 39 | #include <linux/iocontext.h>
|
| 40 | #include <linux/key.h>
|
| 41 | #include <linux/kmsan.h>
|
| 42 | #include <linux/binfmts.h>
|
| 43 | #include <linux/mman.h>
|
| 44 | #include <linux/mmu_notifier.h>
|
| 45 | #include <linux/fs.h>
|
| 46 | #include <linux/mm.h>
|
| 47 | #include <linux/mm_inline.h>
|
| 48 | #include <linux/memblock.h>
|
| 49 | #include <linux/nsproxy.h>
|
| 50 | #include <linux/capability.h>
|
| 51 | #include <linux/cpu.h>
|
| 52 | #include <linux/cgroup.h>
|
| 53 | #include <linux/security.h>
|
| 54 | #include <linux/hugetlb.h>
|
| 55 | #include <linux/seccomp.h>
|
| 56 | #include <linux/swap.h>
|
| 57 | #include <linux/syscalls.h>
|
| 58 | #include <linux/syscall_user_dispatch.h>
|
| 59 | #include <linux/jiffies.h>
|
| 60 | #include <linux/futex.h>
|
| 61 | #include <linux/compat.h>
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| 62 | #include <linux/kthread.h>
|
| 63 | #include <linux/task_io_accounting_ops.h>
|
| 64 | #include <linux/rcupdate.h>
|
| 65 | #include <linux/ptrace.h>
|
| 66 | #include <linux/mount.h>
|
| 67 | #include <linux/audit.h>
|
| 68 | #include <linux/memcontrol.h>
|
| 69 | #include <linux/ftrace.h>
|
| 70 | #include <linux/proc_fs.h>
|
| 71 | #include <linux/profile.h>
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| 72 | #include <linux/rmap.h>
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| 73 | #include <linux/ksm.h>
|
| 74 | #include <linux/acct.h>
|
| 75 | #include <linux/userfaultfd_k.h>
|
| 76 | #include <linux/tsacct_kern.h>
|
| 77 | #include <linux/cn_proc.h>
|
| 78 | #include <linux/freezer.h>
|
| 79 | #include <linux/delayacct.h>
|
| 80 | #include <linux/taskstats_kern.h>
|
| 81 | #include <linux/tty.h>
|
| 82 | #include <linux/fs_struct.h>
|
| 83 | #include <linux/magic.h>
|
| 84 | #include <linux/perf_event.h>
|
| 85 | #include <linux/posix-timers.h>
|
| 86 | #include <linux/user-return-notifier.h>
|
| 87 | #include <linux/oom.h>
|
| 88 | #include <linux/khugepaged.h>
|
| 89 | #include <linux/signalfd.h>
|
| 90 | #include <linux/uprobes.h>
|
| 91 | #include <linux/aio.h>
|
| 92 | #include <linux/compiler.h>
|
| 93 | #include <linux/sysctl.h>
|
| 94 | #include <linux/kcov.h>
|
| 95 | #include <linux/livepatch.h>
|
| 96 | #include <linux/thread_info.h>
|
| 97 | #include <linux/stackleak.h>
|
| 98 | #include <linux/kasan.h>
|
| 99 | #include <linux/scs.h>
|
| 100 | #include <linux/io_uring.h>
|
| 101 | #include <linux/bpf.h>
|
| 102 | #include <linux/stackprotector.h>
|
| 103 | #include <linux/user_events.h>
|
| 104 | #include <linux/iommu.h>
|
| 105 | #include <linux/rseq.h>
|
| 106 | #include <uapi/linux/pidfd.h>
|
| 107 | #include <linux/pidfs.h>
|
| 108 |
|
| 109 | #include <asm/pgalloc.h>
|
| 110 | #include <linux/uaccess.h>
|
| 111 | #include <asm/mmu_context.h>
|
| 112 | #include <asm/cacheflush.h>
|
| 113 | #include <asm/tlbflush.h>
|
| 114 |
|
| 115 | #include <trace/events/sched.h>
|
| 116 |
|
| 117 | #define CREATE_TRACE_POINTS
|
| 118 | #include <trace/events/task.h>
|
| 119 |
|
| 120 | #include <kunit/visibility.h>
|
| 121 |
|
| 122 | |
| 123 | * Minimum number of threads to boot the kernel
|
| 124 |
|
| 125 | #define MIN_THREADS 20
|
| 126 |
|
| 127 | |
| 128 | * Maximum number of threads
|
| 129 |
|
| 130 | #define MAX_THREADS FUTEX_TID_MASK
|
| 131 |
|
| 132 | |
| 133 | * Protected counters by write_lock_irq(&tasklist_lock)
|
| 134 |
|
| 135 | unsigned long total_forks;
|
| 136 | int nr_threads;
|
| 137 |
|
| 138 | static int max_threads;
|
| 139 |
|
| 140 | #define NAMED_ARRAY_INDEX(x) [x] = __stringify(x)
|
| 141 |
|
| 142 | static const char * const resident_page_types[] = {
|
| 143 | NAMED_ARRAY_INDEX(MM_FILEPAGES),
|
| 144 | NAMED_ARRAY_INDEX(MM_ANONPAGES),
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| 145 | NAMED_ARRAY_INDEX(MM_SWAPENTS),
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| 146 | NAMED_ARRAY_INDEX(MM_SHMEMPAGES),
|
| 147 | };
|
| 148 |
|
| 149 | DEFINE_PER_CPU(unsigned long, process_counts) = 0;
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| 150 |
|
| 151 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock);
|
| 152 |
|
| 153 | #ifdef CONFIG_PROVE_RCU
|
| 154 | int lockdep_tasklist_lock_is_held(void)
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| 155 | {
|
| 156 | return lockdep_is_held(&tasklist_lock);
|
| 157 | }
|
| 158 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
|
| 159 | #endif
|
| 160 |
|
| 161 | int nr_processes(void)
|
| 162 | {
|
| 163 | int cpu;
|
| 164 | int total = 0;
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| 165 |
|
| 166 | for_each_possible_cpu(cpu)
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| 167 | total += per_cpu(process_counts, cpu);
|
| 168 |
|
| 169 | return total;
|
| 170 | }
|
| 171 |
|
| 172 | void __weak arch_release_task_struct(struct task_struct *tsk)
|
| 173 | {
|
| 174 | }
|
| 175 |
|
| 176 | static struct kmem_cache *task_struct_cachep;
|
| 177 |
|
| 178 | static inline struct task_struct *alloc_task_struct_node(int node)
|
| 179 | {
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| 180 | return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
|
| 181 | }
|
| 182 |
|
| 183 | static inline void free_task_struct(struct task_struct *tsk)
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| 184 | {
|
| 185 | kmem_cache_free(task_struct_cachep, tsk);
|
| 186 | }
|
| 187 |
|
| 188 | |
| 189 | * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
|
| 190 | * kmemcache based allocator.
|
| 191 |
|
| 192 | # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)
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| 193 |
|
| 194 | # ifdef CONFIG_VMAP_STACK
|
| 195 | |
| 196 | * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
|
| 197 | * flush. Try to minimize the number of calls by caching stacks.
|
| 198 |
|
| 199 | #define NR_CACHED_STACKS 2
|
| 200 | static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
|
| 201 |
|
| 202 | struct vm_stack {
|
| 203 | struct rcu_head rcu;
|
| 204 | struct vm_struct *stack_vm_area;
|
| 205 | };
|
| 206 |
|
| 207 | static bool try_release_thread_stack_to_cache(struct vm_struct *vm)
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| 208 | {
|
| 209 | unsigned int i;
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| 210 |
|
| 211 | for (i = 0; i < NR_CACHED_STACKS; i++) {
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| 212 | struct vm_struct *tmp = NULL;
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| 213 |
|
| 214 | if (this_cpu_try_cmpxchg(cached_stacks[i], &tmp, vm))
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| 215 | return true;
|
| 216 | }
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| 217 | return false;
|
| 218 | }
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| 219 |
|
| 220 | static void thread_stack_free_rcu(struct rcu_head *rh)
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| 221 | {
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| 222 | struct vm_stack *vm_stack = container_of(rh, struct vm_stack, rcu);
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| 223 |
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| 224 | if (try_release_thread_stack_to_cache(vm_stack->stack_vm_area))
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| 225 | return;
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| 226 |
|
| 227 | vfree(vm_stack);
|
| 228 | }
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| 229 |
|
| 230 | static void thread_stack_delayed_free(struct task_struct *tsk)
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| 231 | {
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| 232 | struct vm_stack *vm_stack = tsk->stack;
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| 233 |
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| 234 | vm_stack->stack_vm_area = tsk->stack_vm_area;
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| 235 | call_rcu(&vm_stack->rcu, thread_stack_free_rcu);
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| 236 | }
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| 237 |
|
| 238 | static int free_vm_stack_cache(unsigned int cpu)
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| 239 | {
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| 240 | struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu);
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| 241 | int i;
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| 242 |
|
| 243 | for (i = 0; i < NR_CACHED_STACKS; i++) {
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| 244 | struct vm_struct *vm_stack = cached_vm_stacks[i];
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| 245 |
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| 246 | if (!vm_stack)
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| 247 | continue;
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| 248 |
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| 249 | vfree(vm_stack->addr);
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| 250 | cached_vm_stacks[i] = NULL;
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| 251 | }
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| 252 |
|
| 253 | return 0;
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| 254 | }
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| 255 |
|
| 256 | static int memcg_charge_kernel_stack(struct vm_struct *vm)
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| 257 | {
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| 258 | int i;
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| 259 | int ret;
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| 260 | int nr_charged = 0;
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| 261 |
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| 262 | BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
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| 263 |
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| 264 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
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| 265 | ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0);
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| 266 | if (ret)
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| 267 | goto err;
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| 268 | nr_charged++;
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| 269 | }
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| 270 | return 0;
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| 271 | err:
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| 272 | for (i = 0; i < nr_charged; i++)
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| 273 | memcg_kmem_uncharge_page(vm->pages[i], 0);
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| 274 | return ret;
|
| 275 | }
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| 276 |
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| 277 | static int alloc_thread_stack_node(struct task_struct *tsk, int node)
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| 278 | {
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| 279 | struct vm_struct *vm;
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| 280 | void *stack;
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| 281 | int i;
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| 282 |
|
| 283 | for (i = 0; i < NR_CACHED_STACKS; i++) {
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| 284 | struct vm_struct *s;
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| 285 |
|
| 286 | s = this_cpu_xchg(cached_stacks[i], NULL);
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| 287 |
|
| 288 | if (!s)
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| 289 | continue;
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| 290 |
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| 291 |
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| 292 | kasan_unpoison_range(s->addr, THREAD_SIZE);
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| 293 |
|
| 294 | stack = kasan_reset_tag(s->addr);
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| 295 |
|
| 296 |
|
| 297 | memset(stack, 0, THREAD_SIZE);
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| 298 |
|
| 299 | if (memcg_charge_kernel_stack(s)) {
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| 300 | vfree(s->addr);
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| 301 | return -ENOMEM;
|
| 302 | }
|
| 303 |
|
| 304 | tsk->stack_vm_area = s;
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| 305 | tsk->stack = stack;
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| 306 | return 0;
|
| 307 | }
|
| 308 |
|
| 309 | |
| 310 | * Allocated stacks are cached and later reused by new threads,
|
| 311 | * so memcg accounting is performed manually on assigning/releasing
|
| 312 | * stacks to tasks. Drop __GFP_ACCOUNT.
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| 313 |
|
| 314 | stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN,
|
| 315 | VMALLOC_START, VMALLOC_END,
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| 316 | THREADINFO_GFP & ~__GFP_ACCOUNT,
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| 317 | PAGE_KERNEL,
|
| 318 | 0, node, __builtin_return_address(0));
|
| 319 | if (!stack)
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| 320 | return -ENOMEM;
|
| 321 |
|
| 322 | vm = find_vm_area(stack);
|
| 323 | if (memcg_charge_kernel_stack(vm)) {
|
| 324 | vfree(stack);
|
| 325 | return -ENOMEM;
|
| 326 | }
|
| 327 | |
| 328 | * We can't call find_vm_area() in interrupt context, and
|
| 329 | * free_thread_stack() can be called in interrupt context,
|
| 330 | * so cache the vm_struct.
|
| 331 |
|
| 332 | tsk->stack_vm_area = vm;
|
| 333 | stack = kasan_reset_tag(stack);
|
| 334 | tsk->stack = stack;
|
| 335 | return 0;
|
| 336 | }
|
| 337 |
|
| 338 | static void free_thread_stack(struct task_struct *tsk)
|
| 339 | {
|
| 340 | if (!try_release_thread_stack_to_cache(tsk->stack_vm_area))
|
| 341 | thread_stack_delayed_free(tsk);
|
| 342 |
|
| 343 | tsk->stack = NULL;
|
| 344 | tsk->stack_vm_area = NULL;
|
| 345 | }
|
| 346 |
|
| 347 | # else
|
| 348 |
|
| 349 | static void thread_stack_free_rcu(struct rcu_head *rh)
|
| 350 | {
|
| 351 | __free_pages(virt_to_page(rh), THREAD_SIZE_ORDER);
|
| 352 | }
|
| 353 |
|
| 354 | static void thread_stack_delayed_free(struct task_struct *tsk)
|
| 355 | {
|
| 356 | struct rcu_head *rh = tsk->stack;
|
| 357 |
|
| 358 | call_rcu(rh, thread_stack_free_rcu);
|
| 359 | }
|
| 360 |
|
| 361 | static int alloc_thread_stack_node(struct task_struct *tsk, int node)
|
| 362 | {
|
| 363 | struct page *page = alloc_pages_node(node, THREADINFO_GFP,
|
| 364 | THREAD_SIZE_ORDER);
|
| 365 |
|
| 366 | if (likely(page)) {
|
| 367 | tsk->stack = kasan_reset_tag(page_address(page));
|
| 368 | return 0;
|
| 369 | }
|
| 370 | return -ENOMEM;
|
| 371 | }
|
| 372 |
|
| 373 | static void free_thread_stack(struct task_struct *tsk)
|
| 374 | {
|
| 375 | thread_stack_delayed_free(tsk);
|
| 376 | tsk->stack = NULL;
|
| 377 | }
|
| 378 |
|
| 379 | # endif
|
| 380 | # else
|
| 381 |
|
| 382 | static struct kmem_cache *thread_stack_cache;
|
| 383 |
|
| 384 | static void thread_stack_free_rcu(struct rcu_head *rh)
|
| 385 | {
|
| 386 | kmem_cache_free(thread_stack_cache, rh);
|
| 387 | }
|
| 388 |
|
| 389 | static void thread_stack_delayed_free(struct task_struct *tsk)
|
| 390 | {
|
| 391 | struct rcu_head *rh = tsk->stack;
|
| 392 |
|
| 393 | call_rcu(rh, thread_stack_free_rcu);
|
| 394 | }
|
| 395 |
|
| 396 | static int alloc_thread_stack_node(struct task_struct *tsk, int node)
|
| 397 | {
|
| 398 | unsigned long *stack;
|
| 399 | stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
|
| 400 | stack = kasan_reset_tag(stack);
|
| 401 | tsk->stack = stack;
|
| 402 | return stack ? 0 : -ENOMEM;
|
| 403 | }
|
| 404 |
|
| 405 | static void free_thread_stack(struct task_struct *tsk)
|
| 406 | {
|
| 407 | thread_stack_delayed_free(tsk);
|
| 408 | tsk->stack = NULL;
|
| 409 | }
|
| 410 |
|
| 411 | void thread_stack_cache_init(void)
|
| 412 | {
|
| 413 | thread_stack_cache = kmem_cache_create_usercopy("thread_stack",
|
| 414 | THREAD_SIZE, THREAD_SIZE, 0, 0,
|
| 415 | THREAD_SIZE, NULL);
|
| 416 | BUG_ON(thread_stack_cache == NULL);
|
| 417 | }
|
| 418 |
|
| 419 | # endif
|
| 420 |
|
| 421 |
|
| 422 | static struct kmem_cache *signal_cachep;
|
| 423 |
|
| 424 |
|
| 425 | struct kmem_cache *sighand_cachep;
|
| 426 |
|
| 427 |
|
| 428 | struct kmem_cache *files_cachep;
|
| 429 |
|
| 430 |
|
| 431 | struct kmem_cache *fs_cachep;
|
| 432 |
|
| 433 |
|
| 434 | static struct kmem_cache *vm_area_cachep;
|
| 435 |
|
| 436 |
|
| 437 | static struct kmem_cache *mm_cachep;
|
| 438 |
|
| 439 | #ifdef CONFIG_PER_VMA_LOCK
|
| 440 |
|
| 441 |
|
| 442 | static struct kmem_cache *vma_lock_cachep;
|
| 443 |
|
| 444 | static bool vma_lock_alloc(struct vm_area_struct *vma)
|
| 445 | {
|
| 446 | vma->vm_lock = kmem_cache_alloc(vma_lock_cachep, GFP_KERNEL);
|
| 447 | if (!vma->vm_lock)
|
| 448 | return false;
|
| 449 |
|
| 450 | init_rwsem(&vma->vm_lock->lock);
|
| 451 | vma->vm_lock_seq = -1;
|
| 452 |
|
| 453 | return true;
|
| 454 | }
|
| 455 |
|
| 456 | static inline void vma_lock_free(struct vm_area_struct *vma)
|
| 457 | {
|
| 458 | kmem_cache_free(vma_lock_cachep, vma->vm_lock);
|
| 459 | }
|
| 460 |
|
| 461 | #else
|
| 462 |
|
| 463 | static inline bool vma_lock_alloc(struct vm_area_struct *vma) { return true; }
|
| 464 | static inline void vma_lock_free(struct vm_area_struct *vma) {}
|
| 465 |
|
| 466 | #endif
|
| 467 |
|
| 468 | struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
|
| 469 | {
|
| 470 | struct vm_area_struct *vma;
|
| 471 |
|
| 472 | vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
|
| 473 | if (!vma)
|
| 474 | return NULL;
|
| 475 |
|
| 476 | vma_init(vma, mm);
|
| 477 | if (!vma_lock_alloc(vma)) {
|
| 478 | kmem_cache_free(vm_area_cachep, vma);
|
| 479 | return NULL;
|
| 480 | }
|
| 481 |
|
| 482 | return vma;
|
| 483 | }
|
| 484 |
|
| 485 | struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
|
| 486 | {
|
| 487 | struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
|
| 488 |
|
| 489 | if (!new)
|
| 490 | return NULL;
|
| 491 |
|
| 492 | ASSERT_EXCLUSIVE_WRITER(orig->vm_flags);
|
| 493 | ASSERT_EXCLUSIVE_WRITER(orig->vm_file);
|
| 494 | |
| 495 | * orig->shared.rb may be modified concurrently, but the clone
|
| 496 | * will be reinitialized.
|
| 497 |
|
| 498 | data_race(memcpy(new, orig, sizeof(*new)));
|
| 499 | if (!vma_lock_alloc(new)) {
|
| 500 | kmem_cache_free(vm_area_cachep, new);
|
| 501 | return NULL;
|
| 502 | }
|
| 503 | INIT_LIST_HEAD(&new->anon_vma_chain);
|
| 504 | vma_numab_state_init(new);
|
| 505 | dup_anon_vma_name(orig, new);
|
| 506 |
|
| 507 | return new;
|
| 508 | }
|
| 509 |
|
| 510 | void __vm_area_free(struct vm_area_struct *vma)
|
| 511 | {
|
| 512 | vma_numab_state_free(vma);
|
| 513 | free_anon_vma_name(vma);
|
| 514 | vma_lock_free(vma);
|
| 515 | kmem_cache_free(vm_area_cachep, vma);
|
| 516 | }
|
| 517 |
|
| 518 | #ifdef CONFIG_PER_VMA_LOCK
|
| 519 | static void vm_area_free_rcu_cb(struct rcu_head *head)
|
| 520 | {
|
| 521 | struct vm_area_struct *vma = container_of(head, struct vm_area_struct,
|
| 522 | vm_rcu);
|
| 523 |
|
| 524 |
|
| 525 | VM_BUG_ON_VMA(rwsem_is_locked(&vma->vm_lock->lock), vma);
|
| 526 | __vm_area_free(vma);
|
| 527 | }
|
| 528 | #endif
|
| 529 |
|
| 530 | void vm_area_free(struct vm_area_struct *vma)
|
| 531 | {
|
| 532 | #ifdef CONFIG_PER_VMA_LOCK
|
| 533 | call_rcu(&vma->vm_rcu, vm_area_free_rcu_cb);
|
| 534 | #else
|
| 535 | __vm_area_free(vma);
|
| 536 | #endif
|
| 537 | }
|
| 538 |
|
| 539 | static void account_kernel_stack(struct task_struct *tsk, int account)
|
| 540 | {
|
| 541 | if (IS_ENABLED(CONFIG_VMAP_STACK)) {
|
| 542 | struct vm_struct *vm = task_stack_vm_area(tsk);
|
| 543 | int i;
|
| 544 |
|
| 545 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
|
| 546 | mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB,
|
| 547 | account * (PAGE_SIZE / 1024));
|
| 548 | } else {
|
| 549 | void *stack = task_stack_page(tsk);
|
| 550 |
|
| 551 |
|
| 552 | mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB,
|
| 553 | account * (THREAD_SIZE / 1024));
|
| 554 | }
|
| 555 | }
|
| 556 |
|
| 557 | void exit_task_stack_account(struct task_struct *tsk)
|
| 558 | {
|
| 559 | account_kernel_stack(tsk, -1);
|
| 560 |
|
| 561 | if (IS_ENABLED(CONFIG_VMAP_STACK)) {
|
| 562 | struct vm_struct *vm;
|
| 563 | int i;
|
| 564 |
|
| 565 | vm = task_stack_vm_area(tsk);
|
| 566 | for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
|
| 567 | memcg_kmem_uncharge_page(vm->pages[i], 0);
|
| 568 | }
|
| 569 | }
|
| 570 |
|
| 571 | static void release_task_stack(struct task_struct *tsk)
|
| 572 | {
|
| 573 | if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD))
|
| 574 | return;
|
| 575 |
|
| 576 | free_thread_stack(tsk);
|
| 577 | }
|
| 578 |
|
| 579 | #ifdef CONFIG_THREAD_INFO_IN_TASK
|
| 580 | void put_task_stack(struct task_struct *tsk)
|
| 581 | {
|
| 582 | if (refcount_dec_and_test(&tsk->stack_refcount))
|
| 583 | release_task_stack(tsk);
|
| 584 | }
|
| 585 | #endif
|
| 586 |
|
| 587 | void free_task(struct task_struct *tsk)
|
| 588 | {
|
| 589 | #ifdef CONFIG_SECCOMP
|
| 590 | WARN_ON_ONCE(tsk->seccomp.filter);
|
| 591 | #endif
|
| 592 | release_user_cpus_ptr(tsk);
|
| 593 | scs_release(tsk);
|
| 594 |
|
| 595 | #ifndef CONFIG_THREAD_INFO_IN_TASK
|
| 596 | |
| 597 | * The task is finally done with both the stack and thread_info,
|
| 598 | * so free both.
|
| 599 |
|
| 600 | release_task_stack(tsk);
|
| 601 | #else
|
| 602 | |
| 603 | * If the task had a separate stack allocation, it should be gone
|
| 604 | * by now.
|
| 605 |
|
| 606 | WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);
|
| 607 | #endif
|
| 608 | rt_mutex_debug_task_free(tsk);
|
| 609 | ftrace_graph_exit_task(tsk);
|
| 610 | arch_release_task_struct(tsk);
|
| 611 | if (tsk->flags & PF_KTHREAD)
|
| 612 | free_kthread_struct(tsk);
|
| 613 | bpf_task_storage_free(tsk);
|
| 614 | free_task_struct(tsk);
|
| 615 | }
|
| 616 | EXPORT_SYMBOL(free_task);
|
| 617 |
|
| 618 | static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm)
|
| 619 | {
|
| 620 | struct file *exe_file;
|
| 621 |
|
| 622 | exe_file = get_mm_exe_file(oldmm);
|
| 623 | RCU_INIT_POINTER(mm->exe_file, exe_file);
|
| 624 | }
|
| 625 |
|
| 626 | #ifdef CONFIG_MMU
|
| 627 | static __latent_entropy int dup_mmap(struct mm_struct *mm,
|
| 628 | struct mm_struct *oldmm)
|
| 629 | {
|
| 630 | struct vm_area_struct *mpnt, *tmp;
|
| 631 | int retval;
|
| 632 | unsigned long charge = 0;
|
| 633 | LIST_HEAD(uf);
|
| 634 | VMA_ITERATOR(vmi, mm, 0);
|
| 635 |
|
| 636 | uprobe_start_dup_mmap();
|
| 637 | if (mmap_write_lock_killable(oldmm)) {
|
| 638 | retval = -EINTR;
|
| 639 | goto fail_uprobe_end;
|
| 640 | }
|
| 641 | flush_cache_dup_mm(oldmm);
|
| 642 | uprobe_dup_mmap(oldmm, mm);
|
| 643 | |
| 644 | * Not linked in yet - no deadlock potential:
|
| 645 |
|
| 646 | mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING);
|
| 647 |
|
| 648 |
|
| 649 | dup_mm_exe_file(mm, oldmm);
|
| 650 |
|
| 651 | mm->total_vm = oldmm->total_vm;
|
| 652 | mm->data_vm = oldmm->data_vm;
|
| 653 | mm->exec_vm = oldmm->exec_vm;
|
| 654 | mm->stack_vm = oldmm->stack_vm;
|
| 655 |
|
| 656 | retval = ksm_fork(mm, oldmm);
|
| 657 | if (retval)
|
| 658 | goto out;
|
| 659 | khugepaged_fork(mm, oldmm);
|
| 660 |
|
| 661 |
|
| 662 | retval = __mt_dup(&oldmm->mm_mt, &mm->mm_mt, GFP_KERNEL);
|
| 663 | if (unlikely(retval))
|
| 664 | goto out;
|
| 665 |
|
| 666 | mt_clear_in_rcu(vmi.mas.tree);
|
| 667 | for_each_vma(vmi, mpnt) {
|
| 668 | struct file *file;
|
| 669 |
|
| 670 | vma_start_write(mpnt);
|
| 671 | if (mpnt->vm_flags & VM_DONTCOPY) {
|
| 672 | retval = vma_iter_clear_gfp(&vmi, mpnt->vm_start,
|
| 673 | mpnt->vm_end, GFP_KERNEL);
|
| 674 | if (retval)
|
| 675 | goto loop_out;
|
| 676 |
|
| 677 | vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt));
|
| 678 | continue;
|
| 679 | }
|
| 680 | charge = 0;
|
| 681 | |
| 682 | * Don't duplicate many vmas if we've been oom-killed (for
|
| 683 | * example)
|
| 684 |
|
| 685 | if (fatal_signal_pending(current)) {
|
| 686 | retval = -EINTR;
|
| 687 | goto loop_out;
|
| 688 | }
|
| 689 | if (mpnt->vm_flags & VM_ACCOUNT) {
|
| 690 | unsigned long len = vma_pages(mpnt);
|
| 691 |
|
| 692 | if (security_vm_enough_memory_mm(oldmm, len))
|
| 693 | goto fail_nomem;
|
| 694 | charge = len;
|
| 695 | }
|
| 696 | tmp = vm_area_dup(mpnt);
|
| 697 | if (!tmp)
|
| 698 | goto fail_nomem;
|
| 699 | retval = vma_dup_policy(mpnt, tmp);
|
| 700 | if (retval)
|
| 701 | goto fail_nomem_policy;
|
| 702 | tmp->vm_mm = mm;
|
| 703 | retval = dup_userfaultfd(tmp, &uf);
|
| 704 | if (retval)
|
| 705 | goto fail_nomem_anon_vma_fork;
|
| 706 | if (tmp->vm_flags & VM_WIPEONFORK) {
|
| 707 | |
| 708 | * VM_WIPEONFORK gets a clean slate in the child.
|
| 709 | * Don't prepare anon_vma until fault since we don't
|
| 710 | * copy page for current vma.
|
| 711 |
|
| 712 | tmp->anon_vma = NULL;
|
| 713 | } else if (anon_vma_fork(tmp, mpnt))
|
| 714 | goto fail_nomem_anon_vma_fork;
|
| 715 | vm_flags_clear(tmp, VM_LOCKED_MASK);
|
| 716 | |
| 717 | * Copy/update hugetlb private vma information.
|
| 718 |
|
| 719 | if (is_vm_hugetlb_page(tmp))
|
| 720 | hugetlb_dup_vma_private(tmp);
|
| 721 |
|
| 722 | |
| 723 | * Link the vma into the MT. After using __mt_dup(), memory
|
| 724 | * allocation is not necessary here, so it cannot fail.
|
| 725 |
|
| 726 | vma_iter_bulk_store(&vmi, tmp);
|
| 727 |
|
| 728 | mm->map_count++;
|
| 729 |
|
| 730 | if (tmp->vm_ops && tmp->vm_ops->open)
|
| 731 | tmp->vm_ops->open(tmp);
|
| 732 |
|
| 733 | file = tmp->vm_file;
|
| 734 | if (file) {
|
| 735 | struct address_space *mapping = file->f_mapping;
|
| 736 |
|
| 737 | get_file(file);
|
| 738 | i_mmap_lock_write(mapping);
|
| 739 | if (vma_is_shared_maywrite(tmp))
|
| 740 | mapping_allow_writable(mapping);
|
| 741 | flush_dcache_mmap_lock(mapping);
|
| 742 |
|
| 743 | vma_interval_tree_insert_after(tmp, mpnt,
|
| 744 | &mapping->i_mmap);
|
| 745 | flush_dcache_mmap_unlock(mapping);
|
| 746 | i_mmap_unlock_write(mapping);
|
| 747 | }
|
| 748 |
|
| 749 | if (!(tmp->vm_flags & VM_WIPEONFORK))
|
| 750 | retval = copy_page_range(tmp, mpnt);
|
| 751 |
|
| 752 | if (retval) {
|
| 753 | mpnt = vma_next(&vmi);
|
| 754 | goto loop_out;
|
| 755 | }
|
| 756 | }
|
| 757 |
|
| 758 | retval = arch_dup_mmap(oldmm, mm);
|
| 759 | loop_out:
|
| 760 | vma_iter_free(&vmi);
|
| 761 | if (!retval) {
|
| 762 | mt_set_in_rcu(vmi.mas.tree);
|
| 763 | } else if (mpnt) {
|
| 764 | |
| 765 | * The entire maple tree has already been duplicated. If the
|
| 766 | * mmap duplication fails, mark the failure point with
|
| 767 | * XA_ZERO_ENTRY. In exit_mmap(), if this marker is encountered,
|
| 768 | * stop releasing VMAs that have not been duplicated after this
|
| 769 | * point.
|
| 770 |
|
| 771 | mas_set_range(&vmi.mas, mpnt->vm_start, mpnt->vm_end - 1);
|
| 772 | mas_store(&vmi.mas, XA_ZERO_ENTRY);
|
| 773 | }
|
| 774 | out:
|
| 775 | mmap_write_unlock(mm);
|
| 776 | flush_tlb_mm(oldmm);
|
| 777 | mmap_write_unlock(oldmm);
|
| 778 | dup_userfaultfd_complete(&uf);
|
| 779 | fail_uprobe_end:
|
| 780 | uprobe_end_dup_mmap();
|
| 781 | return retval;
|
| 782 |
|
| 783 | fail_nomem_anon_vma_fork:
|
| 784 | mpol_put(vma_policy(tmp));
|
| 785 | fail_nomem_policy:
|
| 786 | vm_area_free(tmp);
|
| 787 | fail_nomem:
|
| 788 | retval = -ENOMEM;
|
| 789 | vm_unacct_memory(charge);
|
| 790 | goto loop_out;
|
| 791 | }
|
| 792 |
|
| 793 | static inline int mm_alloc_pgd(struct mm_struct *mm)
|
| 794 | {
|
| 795 | mm->pgd = pgd_alloc(mm);
|
| 796 | if (unlikely(!mm->pgd))
|
| 797 | return -ENOMEM;
|
| 798 | return 0;
|
| 799 | }
|
| 800 |
|
| 801 | static inline void mm_free_pgd(struct mm_struct *mm)
|
| 802 | {
|
| 803 | pgd_free(mm, mm->pgd);
|
| 804 | }
|
| 805 | #else
|
| 806 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
|
| 807 | {
|
| 808 | mmap_write_lock(oldmm);
|
| 809 | dup_mm_exe_file(mm, oldmm);
|
| 810 | mmap_write_unlock(oldmm);
|
| 811 | return 0;
|
| 812 | }
|
| 813 | #define mm_alloc_pgd(mm) (0)
|
| 814 | #define mm_free_pgd(mm)
|
| 815 | #endif
|
| 816 |
|
| 817 | static void check_mm(struct mm_struct *mm)
|
| 818 | {
|
| 819 | int i;
|
| 820 |
|
| 821 | BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS,
|
| 822 | "Please make sure 'struct resident_page_types[]' is updated as well");
|
| 823 |
|
| 824 | for (i = 0; i < NR_MM_COUNTERS; i++) {
|
| 825 | long x = percpu_counter_sum(&mm->rss_stat[i]);
|
| 826 |
|
| 827 | if (unlikely(x))
|
| 828 | pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n",
|
| 829 | mm, resident_page_types[i], x);
|
| 830 | }
|
| 831 |
|
| 832 | if (mm_pgtables_bytes(mm))
|
| 833 | pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
|
| 834 | mm_pgtables_bytes(mm));
|
| 835 |
|
| 836 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS)
|
| 837 | VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
|
| 838 | #endif
|
| 839 | }
|
| 840 |
|
| 841 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
|
| 842 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
|
| 843 |
|
| 844 | static void do_check_lazy_tlb(void *arg)
|
| 845 | {
|
| 846 | struct mm_struct *mm = arg;
|
| 847 |
|
| 848 | WARN_ON_ONCE(current->active_mm == mm);
|
| 849 | }
|
| 850 |
|
| 851 | static void do_shoot_lazy_tlb(void *arg)
|
| 852 | {
|
| 853 | struct mm_struct *mm = arg;
|
| 854 |
|
| 855 | if (current->active_mm == mm) {
|
| 856 | WARN_ON_ONCE(current->mm);
|
| 857 | current->active_mm = &init_mm;
|
| 858 | switch_mm(mm, &init_mm, current);
|
| 859 | }
|
| 860 | }
|
| 861 |
|
| 862 | static void cleanup_lazy_tlbs(struct mm_struct *mm)
|
| 863 | {
|
| 864 | if (!IS_ENABLED(CONFIG_MMU_LAZY_TLB_SHOOTDOWN)) {
|
| 865 | |
| 866 | * In this case, lazy tlb mms are refounted and would not reach
|
| 867 | * __mmdrop until all CPUs have switched away and mmdrop()ed.
|
| 868 |
|
| 869 | return;
|
| 870 | }
|
| 871 |
|
| 872 | |
| 873 | * Lazy mm shootdown does not refcount "lazy tlb mm" usage, rather it
|
| 874 | * requires lazy mm users to switch to another mm when the refcount
|
| 875 | * drops to zero, before the mm is freed. This requires IPIs here to
|
| 876 | * switch kernel threads to init_mm.
|
| 877 | *
|
| 878 | * archs that use IPIs to flush TLBs can piggy-back that lazy tlb mm
|
| 879 | * switch with the final userspace teardown TLB flush which leaves the
|
| 880 | * mm lazy on this CPU but no others, reducing the need for additional
|
| 881 | * IPIs here. There are cases where a final IPI is still required here,
|
| 882 | * such as the final mmdrop being performed on a different CPU than the
|
| 883 | * one exiting, or kernel threads using the mm when userspace exits.
|
| 884 | *
|
| 885 | * IPI overheads have not found to be expensive, but they could be
|
| 886 | * reduced in a number of possible ways, for example (roughly
|
| 887 | * increasing order of complexity):
|
| 888 | * - The last lazy reference created by exit_mm() could instead switch
|
| 889 | * to init_mm, however it's probable this will run on the same CPU
|
| 890 | * immediately afterwards, so this may not reduce IPIs much.
|
| 891 | * - A batch of mms requiring IPIs could be gathered and freed at once.
|
| 892 | * - CPUs store active_mm where it can be remotely checked without a
|
| 893 | * lock, to filter out false-positives in the cpumask.
|
| 894 | * - After mm_users or mm_count reaches zero, switching away from the
|
| 895 | * mm could clear mm_cpumask to reduce some IPIs, perhaps together
|
| 896 | * with some batching or delaying of the final IPIs.
|
| 897 | * - A delayed freeing and RCU-like quiescing sequence based on mm
|
| 898 | * switching to avoid IPIs completely.
|
| 899 |
|
| 900 | on_each_cpu_mask(mm_cpumask(mm), do_shoot_lazy_tlb, (void *)mm, 1);
|
| 901 | if (IS_ENABLED(CONFIG_DEBUG_VM_SHOOT_LAZIES))
|
| 902 | on_each_cpu(do_check_lazy_tlb, (void *)mm, 1);
|
| 903 | }
|
| 904 |
|
| 905 | |
| 906 | * Called when the last reference to the mm
|
| 907 | * is dropped: either by a lazy thread or by
|
| 908 | * mmput. Free the page directory and the mm.
|
| 909 |
|
| 910 | void __mmdrop(struct mm_struct *mm)
|
| 911 | {
|
| 912 | BUG_ON(mm == &init_mm);
|
| 913 | WARN_ON_ONCE(mm == current->mm);
|
| 914 |
|
| 915 |
|
| 916 | cleanup_lazy_tlbs(mm);
|
| 917 |
|
| 918 | WARN_ON_ONCE(mm == current->active_mm);
|
| 919 | mm_free_pgd(mm);
|
| 920 | destroy_context(mm);
|
| 921 | mmu_notifier_subscriptions_destroy(mm);
|
| 922 | check_mm(mm);
|
| 923 | put_user_ns(mm->user_ns);
|
| 924 | mm_pasid_drop(mm);
|
| 925 | mm_destroy_cid(mm);
|
| 926 | percpu_counter_destroy_many(mm->rss_stat, NR_MM_COUNTERS);
|
| 927 |
|
| 928 | free_mm(mm);
|
| 929 | }
|
| 930 | EXPORT_SYMBOL_GPL(__mmdrop);
|
| 931 |
|
| 932 | static void mmdrop_async_fn(struct work_struct *work)
|
| 933 | {
|
| 934 | struct mm_struct *mm;
|
| 935 |
|
| 936 | mm = container_of(work, struct mm_struct, async_put_work);
|
| 937 | __mmdrop(mm);
|
| 938 | }
|
| 939 |
|
| 940 | static void mmdrop_async(struct mm_struct *mm)
|
| 941 | {
|
| 942 | if (unlikely(atomic_dec_and_test(&mm->mm_count))) {
|
| 943 | INIT_WORK(&mm->async_put_work, mmdrop_async_fn);
|
| 944 | schedule_work(&mm->async_put_work);
|
| 945 | }
|
| 946 | }
|
| 947 |
|
| 948 | static inline void free_signal_struct(struct signal_struct *sig)
|
| 949 | {
|
| 950 | taskstats_tgid_free(sig);
|
| 951 | sched_autogroup_exit(sig);
|
| 952 | |
| 953 | * __mmdrop is not safe to call from softirq context on x86 due to
|
| 954 | * pgd_dtor so postpone it to the async context
|
| 955 |
|
| 956 | if (sig->oom_mm)
|
| 957 | mmdrop_async(sig->oom_mm);
|
| 958 | kmem_cache_free(signal_cachep, sig);
|
| 959 | }
|
| 960 |
|
| 961 | static inline void put_signal_struct(struct signal_struct *sig)
|
| 962 | {
|
| 963 | if (refcount_dec_and_test(&sig->sigcnt))
|
| 964 | free_signal_struct(sig);
|
| 965 | }
|
| 966 |
|
| 967 | void __put_task_struct(struct task_struct *tsk)
|
| 968 | {
|
| 969 | WARN_ON(!tsk->exit_state);
|
| 970 | WARN_ON(refcount_read(&tsk->usage));
|
| 971 | WARN_ON(tsk == current);
|
| 972 |
|
| 973 | sched_ext_free(tsk);
|
| 974 | io_uring_free(tsk);
|
| 975 | cgroup_free(tsk);
|
| 976 | task_numa_free(tsk, true);
|
| 977 | security_task_free(tsk);
|
| 978 | exit_creds(tsk);
|
| 979 | delayacct_tsk_free(tsk);
|
| 980 | put_signal_struct(tsk->signal);
|
| 981 | sched_core_free(tsk);
|
| 982 | free_task(tsk);
|
| 983 | }
|
| 984 | EXPORT_SYMBOL_GPL(__put_task_struct);
|
| 985 |
|
| 986 | void __put_task_struct_rcu_cb(struct rcu_head *rhp)
|
| 987 | {
|
| 988 | struct task_struct *task = container_of(rhp, struct task_struct, rcu);
|
| 989 |
|
| 990 | __put_task_struct(task);
|
| 991 | }
|
| 992 | EXPORT_SYMBOL_GPL(__put_task_struct_rcu_cb);
|
| 993 |
|
| 994 | void __init __weak arch_task_cache_init(void) { }
|
| 995 |
|
| 996 | |
| 997 | * set_max_threads
|
| 998 |
|
| 999 | static void __init set_max_threads(unsigned int max_threads_suggested)
|
| 1000 | {
|
| 1001 | u64 threads;
|
| 1002 | unsigned long nr_pages = memblock_estimated_nr_free_pages();
|
| 1003 |
|
| 1004 | |
| 1005 | * The number of threads shall be limited such that the thread
|
| 1006 | * structures may only consume a small part of the available memory.
|
| 1007 |
|
| 1008 | if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64)
|
| 1009 | threads = MAX_THREADS;
|
| 1010 | else
|
| 1011 | threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE,
|
| 1012 | (u64) THREAD_SIZE * 8UL);
|
| 1013 |
|
| 1014 | if (threads > max_threads_suggested)
|
| 1015 | threads = max_threads_suggested;
|
| 1016 |
|
| 1017 | max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS);
|
| 1018 | }
|
| 1019 |
|
| 1020 | #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
|
| 1021 |
|
| 1022 | int arch_task_struct_size __read_mostly;
|
| 1023 | #endif
|
| 1024 |
|
| 1025 | static void __init task_struct_whitelist(unsigned long *offset, unsigned long *size)
|
| 1026 | {
|
| 1027 |
|
| 1028 | arch_thread_struct_whitelist(offset, size);
|
| 1029 |
|
| 1030 | |
| 1031 | * Handle zero-sized whitelist or empty thread_struct, otherwise
|
| 1032 | * adjust offset to position of thread_struct in task_struct.
|
| 1033 |
|
| 1034 | if (unlikely(*size == 0))
|
| 1035 | *offset = 0;
|
| 1036 | else
|
| 1037 | *offset += offsetof(struct task_struct, thread);
|
| 1038 | }
|
| 1039 |
|
| 1040 | void __init fork_init(void)
|
| 1041 | {
|
| 1042 | int i;
|
| 1043 | #ifndef ARCH_MIN_TASKALIGN
|
| 1044 | #define ARCH_MIN_TASKALIGN 0
|
| 1045 | #endif
|
| 1046 | int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN);
|
| 1047 | unsigned long useroffset, usersize;
|
| 1048 |
|
| 1049 |
|
| 1050 | task_struct_whitelist(&useroffset, &usersize);
|
| 1051 | task_struct_cachep = kmem_cache_create_usercopy("task_struct",
|
| 1052 | arch_task_struct_size, align,
|
| 1053 | SLAB_PANIC|SLAB_ACCOUNT,
|
| 1054 | useroffset, usersize, NULL);
|
| 1055 |
|
| 1056 |
|
| 1057 | arch_task_cache_init();
|
| 1058 |
|
| 1059 | set_max_threads(MAX_THREADS);
|
| 1060 |
|
| 1061 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
|
| 1062 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
|
| 1063 | init_task.signal->rlim[RLIMIT_SIGPENDING] =
|
| 1064 | init_task.signal->rlim[RLIMIT_NPROC];
|
| 1065 |
|
| 1066 | for (i = 0; i < UCOUNT_COUNTS; i++)
|
| 1067 | init_user_ns.ucount_max[i] = max_threads/2;
|
| 1068 |
|
| 1069 | set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY);
|
| 1070 | set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY);
|
| 1071 | set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY);
|
| 1072 | set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY);
|
| 1073 |
|
| 1074 | #ifdef CONFIG_VMAP_STACK
|
| 1075 | cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache",
|
| 1076 | NULL, free_vm_stack_cache);
|
| 1077 | #endif
|
| 1078 |
|
| 1079 | scs_init();
|
| 1080 |
|
| 1081 | lockdep_init_task(&init_task);
|
| 1082 | uprobes_init();
|
| 1083 | }
|
| 1084 |
|
| 1085 | int __weak arch_dup_task_struct(struct task_struct *dst,
|
| 1086 | struct task_struct *src)
|
| 1087 | {
|
| 1088 | *dst = *src;
|
| 1089 | return 0;
|
| 1090 | }
|
| 1091 |
|
| 1092 | void set_task_stack_end_magic(struct task_struct *tsk)
|
| 1093 | {
|
| 1094 | unsigned long *stackend;
|
| 1095 |
|
| 1096 | stackend = end_of_stack(tsk);
|
| 1097 | *stackend = STACK_END_MAGIC;
|
| 1098 | }
|
| 1099 |
|
| 1100 | static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
|
| 1101 | {
|
| 1102 | struct task_struct *tsk;
|
| 1103 | int err;
|
| 1104 |
|
| 1105 | if (node == NUMA_NO_NODE)
|
| 1106 | node = tsk_fork_get_node(orig);
|
| 1107 | tsk = alloc_task_struct_node(node);
|
| 1108 | if (!tsk)
|
| 1109 | return NULL;
|
| 1110 |
|
| 1111 | err = arch_dup_task_struct(tsk, orig);
|
| 1112 | if (err)
|
| 1113 | goto free_tsk;
|
| 1114 |
|
| 1115 | err = alloc_thread_stack_node(tsk, node);
|
| 1116 | if (err)
|
| 1117 | goto free_tsk;
|
| 1118 |
|
| 1119 | #ifdef CONFIG_THREAD_INFO_IN_TASK
|
| 1120 | refcount_set(&tsk->stack_refcount, 1);
|
| 1121 | #endif
|
| 1122 | account_kernel_stack(tsk, 1);
|
| 1123 |
|
| 1124 | err = scs_prepare(tsk, node);
|
| 1125 | if (err)
|
| 1126 | goto free_stack;
|
| 1127 |
|
| 1128 | #ifdef CONFIG_SECCOMP
|
| 1129 | |
| 1130 | * We must handle setting up seccomp filters once we're under
|
| 1131 | * the sighand lock in case orig has changed between now and
|
| 1132 | * then. Until then, filter must be NULL to avoid messing up
|
| 1133 | * the usage counts on the error path calling free_task.
|
| 1134 |
|
| 1135 | tsk->seccomp.filter = NULL;
|
| 1136 | #endif
|
| 1137 |
|
| 1138 | setup_thread_stack(tsk, orig);
|
| 1139 | clear_user_return_notifier(tsk);
|
| 1140 | clear_tsk_need_resched(tsk);
|
| 1141 | set_task_stack_end_magic(tsk);
|
| 1142 | clear_syscall_work_syscall_user_dispatch(tsk);
|
| 1143 |
|
| 1144 | #ifdef CONFIG_STACKPROTECTOR
|
| 1145 | tsk->stack_canary = get_random_canary();
|
| 1146 | #endif
|
| 1147 | if (orig->cpus_ptr == &orig->cpus_mask)
|
| 1148 | tsk->cpus_ptr = &tsk->cpus_mask;
|
| 1149 | dup_user_cpus_ptr(tsk, orig, node);
|
| 1150 |
|
| 1151 | |
| 1152 | * One for the user space visible state that goes away when reaped.
|
| 1153 | * One for the scheduler.
|
| 1154 |
|
| 1155 | refcount_set(&tsk->rcu_users, 2);
|
| 1156 |
|
| 1157 | refcount_set(&tsk->usage, 1);
|
| 1158 | #ifdef CONFIG_BLK_DEV_IO_TRACE
|
| 1159 | tsk->btrace_seq = 0;
|
| 1160 | #endif
|
| 1161 | tsk->splice_pipe = NULL;
|
| 1162 | tsk->task_frag.page = NULL;
|
| 1163 | tsk->wake_q.next = NULL;
|
| 1164 | tsk->worker_private = NULL;
|
| 1165 |
|
| 1166 | kcov_task_init(tsk);
|
| 1167 | kmsan_task_create(tsk);
|
| 1168 | kmap_local_fork(tsk);
|
| 1169 |
|
| 1170 | #ifdef CONFIG_FAULT_INJECTION
|
| 1171 | tsk->fail_nth = 0;
|
| 1172 | #endif
|
| 1173 |
|
| 1174 | #ifdef CONFIG_BLK_CGROUP
|
| 1175 | tsk->throttle_disk = NULL;
|
| 1176 | tsk->use_memdelay = 0;
|
| 1177 | #endif
|
| 1178 |
|
| 1179 | #ifdef CONFIG_ARCH_HAS_CPU_PASID
|
| 1180 | tsk->pasid_activated = 0;
|
| 1181 | #endif
|
| 1182 |
|
| 1183 | #ifdef CONFIG_MEMCG
|
| 1184 | tsk->active_memcg = NULL;
|
| 1185 | #endif
|
| 1186 |
|
| 1187 | #ifdef CONFIG_CPU_SUP_INTEL
|
| 1188 | tsk->reported_split_lock = 0;
|
| 1189 | #endif
|
| 1190 |
|
| 1191 | #ifdef CONFIG_SCHED_MM_CID
|
| 1192 | tsk->mm_cid = -1;
|
| 1193 | tsk->last_mm_cid = -1;
|
| 1194 | tsk->mm_cid_active = 0;
|
| 1195 | tsk->migrate_from_cpu = -1;
|
| 1196 | #endif
|
| 1197 | return tsk;
|
| 1198 |
|
| 1199 | free_stack:
|
| 1200 | exit_task_stack_account(tsk);
|
| 1201 | free_thread_stack(tsk);
|
| 1202 | free_tsk:
|
| 1203 | free_task_struct(tsk);
|
| 1204 | return NULL;
|
| 1205 | }
|
| 1206 |
|
| 1207 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
|
| 1208 |
|
| 1209 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT;
|
| 1210 |
|
| 1211 | static int __init coredump_filter_setup(char *s)
|
| 1212 | {
|
| 1213 | default_dump_filter =
|
| 1214 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) &
|
| 1215 | MMF_DUMP_FILTER_MASK;
|
| 1216 | return 1;
|
| 1217 | }
|
| 1218 |
|
| 1219 | __setup("coredump_filter=", coredump_filter_setup);
|
| 1220 |
|
| 1221 | #include <linux/init_task.h>
|
| 1222 |
|
| 1223 | static void mm_init_aio(struct mm_struct *mm)
|
| 1224 | {
|
| 1225 | #ifdef CONFIG_AIO
|
| 1226 | spin_lock_init(&mm->ioctx_lock);
|
| 1227 | mm->ioctx_table = NULL;
|
| 1228 | #endif
|
| 1229 | }
|
| 1230 |
|
| 1231 | static __always_inline void mm_clear_owner(struct mm_struct *mm,
|
| 1232 | struct task_struct *p)
|
| 1233 | {
|
| 1234 | #ifdef CONFIG_MEMCG
|
| 1235 | if (mm->owner == p)
|
| 1236 | WRITE_ONCE(mm->owner, NULL);
|
| 1237 | #endif
|
| 1238 | }
|
| 1239 |
|
| 1240 | static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
|
| 1241 | {
|
| 1242 | #ifdef CONFIG_MEMCG
|
| 1243 | mm->owner = p;
|
| 1244 | #endif
|
| 1245 | }
|
| 1246 |
|
| 1247 | static void mm_init_uprobes_state(struct mm_struct *mm)
|
| 1248 | {
|
| 1249 | #ifdef CONFIG_UPROBES
|
| 1250 | mm->uprobes_state.xol_area = NULL;
|
| 1251 | #endif
|
| 1252 | }
|
| 1253 |
|
| 1254 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
|
| 1255 | struct user_namespace *user_ns)
|
| 1256 | {
|
| 1257 | mt_init_flags(&mm->mm_mt, MM_MT_FLAGS);
|
| 1258 | mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock);
|
| 1259 | atomic_set(&mm->mm_users, 1);
|
| 1260 | atomic_set(&mm->mm_count, 1);
|
| 1261 | seqcount_init(&mm->write_protect_seq);
|
| 1262 | mmap_init_lock(mm);
|
| 1263 | INIT_LIST_HEAD(&mm->mmlist);
|
| 1264 | #ifdef CONFIG_PER_VMA_LOCK
|
| 1265 | mm->mm_lock_seq = 0;
|
| 1266 | #endif
|
| 1267 | mm_pgtables_bytes_init(mm);
|
| 1268 | mm->map_count = 0;
|
| 1269 | mm->locked_vm = 0;
|
| 1270 | atomic64_set(&mm->pinned_vm, 0);
|
| 1271 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
|
| 1272 | spin_lock_init(&mm->page_table_lock);
|
| 1273 | spin_lock_init(&mm->arg_lock);
|
| 1274 | mm_init_cpumask(mm);
|
| 1275 | mm_init_aio(mm);
|
| 1276 | mm_init_owner(mm, p);
|
| 1277 | mm_pasid_init(mm);
|
| 1278 | RCU_INIT_POINTER(mm->exe_file, NULL);
|
| 1279 | mmu_notifier_subscriptions_init(mm);
|
| 1280 | init_tlb_flush_pending(mm);
|
| 1281 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS)
|
| 1282 | mm->pmd_huge_pte = NULL;
|
| 1283 | #endif
|
| 1284 | mm_init_uprobes_state(mm);
|
| 1285 | hugetlb_count_init(mm);
|
| 1286 |
|
| 1287 | if (current->mm) {
|
| 1288 | mm->flags = mmf_init_flags(current->mm->flags);
|
| 1289 | mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK;
|
| 1290 | } else {
|
| 1291 | mm->flags = default_dump_filter;
|
| 1292 | mm->def_flags = 0;
|
| 1293 | }
|
| 1294 |
|
| 1295 | if (mm_alloc_pgd(mm))
|
| 1296 | goto fail_nopgd;
|
| 1297 |
|
| 1298 | if (init_new_context(p, mm))
|
| 1299 | goto fail_nocontext;
|
| 1300 |
|
| 1301 | if (mm_alloc_cid(mm))
|
| 1302 | goto fail_cid;
|
| 1303 |
|
| 1304 | if (percpu_counter_init_many(mm->rss_stat, 0, GFP_KERNEL_ACCOUNT,
|
| 1305 | NR_MM_COUNTERS))
|
| 1306 | goto fail_pcpu;
|
| 1307 |
|
| 1308 | mm->user_ns = get_user_ns(user_ns);
|
| 1309 | lru_gen_init_mm(mm);
|
| 1310 | return mm;
|
| 1311 |
|
| 1312 | fail_pcpu:
|
| 1313 | mm_destroy_cid(mm);
|
| 1314 | fail_cid:
|
| 1315 | destroy_context(mm);
|
| 1316 | fail_nocontext:
|
| 1317 | mm_free_pgd(mm);
|
| 1318 | fail_nopgd:
|
| 1319 | free_mm(mm);
|
| 1320 | return NULL;
|
| 1321 | }
|
| 1322 |
|
| 1323 | |
| 1324 | * Allocate and initialize an mm_struct.
|
| 1325 |
|
| 1326 | struct mm_struct *mm_alloc(void)
|
| 1327 | {
|
| 1328 | struct mm_struct *mm;
|
| 1329 |
|
| 1330 | mm = allocate_mm();
|
| 1331 | if (!mm)
|
| 1332 | return NULL;
|
| 1333 |
|
| 1334 | memset(mm, 0, sizeof(*mm));
|
| 1335 | return mm_init(mm, current, current_user_ns());
|
| 1336 | }
|
| 1337 | EXPORT_SYMBOL_IF_KUNIT(mm_alloc);
|
| 1338 |
|
| 1339 | static inline void __mmput(struct mm_struct *mm)
|
| 1340 | {
|
| 1341 | VM_BUG_ON(atomic_read(&mm->mm_users));
|
| 1342 |
|
| 1343 | uprobe_clear_state(mm);
|
| 1344 | exit_aio(mm);
|
| 1345 | ksm_exit(mm);
|
| 1346 | khugepaged_exit(mm);
|
| 1347 | exit_mmap(mm);
|
| 1348 | mm_put_huge_zero_folio(mm);
|
| 1349 | set_mm_exe_file(mm, NULL);
|
| 1350 | if (!list_empty(&mm->mmlist)) {
|
| 1351 | spin_lock(&mmlist_lock);
|
| 1352 | list_del(&mm->mmlist);
|
| 1353 | spin_unlock(&mmlist_lock);
|
| 1354 | }
|
| 1355 | if (mm->binfmt)
|
| 1356 | module_put(mm->binfmt->module);
|
| 1357 | lru_gen_del_mm(mm);
|
| 1358 | mmdrop(mm);
|
| 1359 | }
|
| 1360 |
|
| 1361 | |
| 1362 | * Decrement the use count and release all resources for an mm.
|
| 1363 |
|
| 1364 | void mmput(struct mm_struct *mm)
|
| 1365 | {
|
| 1366 | might_sleep();
|
| 1367 |
|
| 1368 | if (atomic_dec_and_test(&mm->mm_users))
|
| 1369 | __mmput(mm);
|
| 1370 | }
|
| 1371 | EXPORT_SYMBOL_GPL(mmput);
|
| 1372 |
|
| 1373 | #ifdef CONFIG_MMU
|
| 1374 | static void mmput_async_fn(struct work_struct *work)
|
| 1375 | {
|
| 1376 | struct mm_struct *mm = container_of(work, struct mm_struct,
|
| 1377 | async_put_work);
|
| 1378 |
|
| 1379 | __mmput(mm);
|
| 1380 | }
|
| 1381 |
|
| 1382 | void mmput_async(struct mm_struct *mm)
|
| 1383 | {
|
| 1384 | if (atomic_dec_and_test(&mm->mm_users)) {
|
| 1385 | INIT_WORK(&mm->async_put_work, mmput_async_fn);
|
| 1386 | schedule_work(&mm->async_put_work);
|
| 1387 | }
|
| 1388 | }
|
| 1389 | EXPORT_SYMBOL_GPL(mmput_async);
|
| 1390 | #endif
|
| 1391 |
|
| 1392 | |
| 1393 | * set_mm_exe_file - change a reference to the mm's executable file
|
| 1394 | * @mm: The mm to change.
|
| 1395 | * @new_exe_file: The new file to use.
|
| 1396 | *
|
| 1397 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe).
|
| 1398 | *
|
| 1399 | * Main users are mmput() and sys_execve(). Callers prevent concurrent
|
| 1400 | * invocations: in mmput() nobody alive left, in execve it happens before
|
| 1401 | * the new mm is made visible to anyone.
|
| 1402 | *
|
| 1403 | * Can only fail if new_exe_file != NULL.
|
| 1404 |
|
| 1405 | int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
|
| 1406 | {
|
| 1407 | struct file *old_exe_file;
|
| 1408 |
|
| 1409 | |
| 1410 | * It is safe to dereference the exe_file without RCU as
|
| 1411 | * this function is only called if nobody else can access
|
| 1412 | * this mm -- see comment above for justification.
|
| 1413 |
|
| 1414 | old_exe_file = rcu_dereference_raw(mm->exe_file);
|
| 1415 |
|
| 1416 | if (new_exe_file)
|
| 1417 | get_file(new_exe_file);
|
| 1418 | rcu_assign_pointer(mm->exe_file, new_exe_file);
|
| 1419 | if (old_exe_file)
|
| 1420 | fput(old_exe_file);
|
| 1421 | return 0;
|
| 1422 | }
|
| 1423 |
|
| 1424 | |
| 1425 | * replace_mm_exe_file - replace a reference to the mm's executable file
|
| 1426 | * @mm: The mm to change.
|
| 1427 | * @new_exe_file: The new file to use.
|
| 1428 | *
|
| 1429 | * This changes mm's executable file (shown as symlink /proc/[pid]/exe).
|
| 1430 | *
|
| 1431 | * Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE).
|
| 1432 |
|
| 1433 | int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
|
| 1434 | {
|
| 1435 | struct vm_area_struct *vma;
|
| 1436 | struct file *old_exe_file;
|
| 1437 | int ret = 0;
|
| 1438 |
|
| 1439 |
|
| 1440 | old_exe_file = get_mm_exe_file(mm);
|
| 1441 | if (old_exe_file) {
|
| 1442 | VMA_ITERATOR(vmi, mm, 0);
|
| 1443 | mmap_read_lock(mm);
|
| 1444 | for_each_vma(vmi, vma) {
|
| 1445 | if (!vma->vm_file)
|
| 1446 | continue;
|
| 1447 | if (path_equal(&vma->vm_file->f_path,
|
| 1448 | &old_exe_file->f_path)) {
|
| 1449 | ret = -EBUSY;
|
| 1450 | break;
|
| 1451 | }
|
| 1452 | }
|
| 1453 | mmap_read_unlock(mm);
|
| 1454 | fput(old_exe_file);
|
| 1455 | if (ret)
|
| 1456 | return ret;
|
| 1457 | }
|
| 1458 |
|
| 1459 | get_file(new_exe_file);
|
| 1460 |
|
| 1461 |
|
| 1462 | mmap_write_lock(mm);
|
| 1463 | old_exe_file = rcu_dereference_raw(mm->exe_file);
|
| 1464 | rcu_assign_pointer(mm->exe_file, new_exe_file);
|
| 1465 | mmap_write_unlock(mm);
|
| 1466 |
|
| 1467 | if (old_exe_file)
|
| 1468 | fput(old_exe_file);
|
| 1469 | return 0;
|
| 1470 | }
|
| 1471 |
|
| 1472 | |
| 1473 | * get_mm_exe_file - acquire a reference to the mm's executable file
|
| 1474 | * @mm: The mm of interest.
|
| 1475 | *
|
| 1476 | * Returns %NULL if mm has no associated executable file.
|
| 1477 | * User must release file via fput().
|
| 1478 |
|
| 1479 | struct file *get_mm_exe_file(struct mm_struct *mm)
|
| 1480 | {
|
| 1481 | struct file *exe_file;
|
| 1482 |
|
| 1483 | rcu_read_lock();
|
| 1484 | exe_file = get_file_rcu(&mm->exe_file);
|
| 1485 | rcu_read_unlock();
|
| 1486 | return exe_file;
|
| 1487 | }
|
| 1488 |
|
| 1489 | |
| 1490 | * get_task_exe_file - acquire a reference to the task's executable file
|
| 1491 | * @task: The task.
|
| 1492 | *
|
| 1493 | * Returns %NULL if task's mm (if any) has no associated executable file or
|
| 1494 | * this is a kernel thread with borrowed mm (see the comment above get_task_mm).
|
| 1495 | * User must release file via fput().
|
| 1496 |
|
| 1497 | struct file *get_task_exe_file(struct task_struct *task)
|
| 1498 | {
|
| 1499 | struct file *exe_file = NULL;
|
| 1500 | struct mm_struct *mm;
|
| 1501 |
|
| 1502 | task_lock(task);
|
| 1503 | mm = task->mm;
|
| 1504 | if (mm) {
|
| 1505 | if (!(task->flags & PF_KTHREAD))
|
| 1506 | exe_file = get_mm_exe_file(mm);
|
| 1507 | }
|
| 1508 | task_unlock(task);
|
| 1509 | return exe_file;
|
| 1510 | }
|
| 1511 |
|
| 1512 | |
| 1513 | * get_task_mm - acquire a reference to the task's mm
|
| 1514 | * @task: The task.
|
| 1515 | *
|
| 1516 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning
|
| 1517 | * this kernel workthread has transiently adopted a user mm with use_mm,
|
| 1518 | * to do its AIO) is not set and if so returns a reference to it, after
|
| 1519 | * bumping up the use count. User must release the mm via mmput()
|
| 1520 | * after use. Typically used by /proc and ptrace.
|
| 1521 |
|
| 1522 | struct mm_struct *get_task_mm(struct task_struct *task)
|
| 1523 | {
|
| 1524 | struct mm_struct *mm;
|
| 1525 |
|
| 1526 | if (task->flags & PF_KTHREAD)
|
| 1527 | return NULL;
|
| 1528 |
|
| 1529 | task_lock(task);
|
| 1530 | mm = task->mm;
|
| 1531 | if (mm)
|
| 1532 | mmget(mm);
|
| 1533 | task_unlock(task);
|
| 1534 | return mm;
|
| 1535 | }
|
| 1536 | EXPORT_SYMBOL_GPL(get_task_mm);
|
| 1537 |
|
| 1538 | struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
|
| 1539 | {
|
| 1540 | struct mm_struct *mm;
|
| 1541 | int err;
|
| 1542 |
|
| 1543 | err = down_read_killable(&task->signal->exec_update_lock);
|
| 1544 | if (err)
|
| 1545 | return ERR_PTR(err);
|
| 1546 |
|
| 1547 | mm = get_task_mm(task);
|
| 1548 | if (mm && mm != current->mm &&
|
| 1549 | !ptrace_may_access(task, mode)) {
|
| 1550 | mmput(mm);
|
| 1551 | mm = ERR_PTR(-EACCES);
|
| 1552 | }
|
| 1553 | up_read(&task->signal->exec_update_lock);
|
| 1554 |
|
| 1555 | return mm;
|
| 1556 | }
|
| 1557 |
|
| 1558 | static void complete_vfork_done(struct task_struct *tsk)
|
| 1559 | {
|
| 1560 | struct completion *vfork;
|
| 1561 |
|
| 1562 | task_lock(tsk);
|
| 1563 | vfork = tsk->vfork_done;
|
| 1564 | if (likely(vfork)) {
|
| 1565 | tsk->vfork_done = NULL;
|
| 1566 | complete(vfork);
|
| 1567 | }
|
| 1568 | task_unlock(tsk);
|
| 1569 | }
|
| 1570 |
|
| 1571 | static int wait_for_vfork_done(struct task_struct *child,
|
| 1572 | struct completion *vfork)
|
| 1573 | {
|
| 1574 | unsigned int state = TASK_KILLABLE|TASK_FREEZABLE;
|
| 1575 | int killed;
|
| 1576 |
|
| 1577 | cgroup_enter_frozen();
|
| 1578 | killed = wait_for_completion_state(vfork, state);
|
| 1579 | cgroup_leave_frozen(false);
|
| 1580 |
|
| 1581 | if (killed) {
|
| 1582 | task_lock(child);
|
| 1583 | child->vfork_done = NULL;
|
| 1584 | task_unlock(child);
|
| 1585 | }
|
| 1586 |
|
| 1587 | put_task_struct(child);
|
| 1588 | return killed;
|
| 1589 | }
|
| 1590 |
|
| 1591 | |
| 1592 | * mmput is called whenever we stop holding onto a mm_struct,
|
| 1593 | * error success whatever.
|
| 1594 | *
|
| 1595 | * mm_release is called after a mm_struct has been removed
|
| 1596 | * from the current process.
|
| 1597 | *
|
| 1598 | * This difference is important for error handling, when we
|
| 1599 | * only half set up a mm_struct for a new process and need to restore
|
| 1600 | * the old one. Because we mmput the new mm_struct before
|
| 1601 | * restoring the old one. . .
|
| 1602 | * Eric Biederman 10 January 1998
|
| 1603 |
|
| 1604 | static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
|
| 1605 | {
|
| 1606 | uprobe_free_utask(tsk);
|
| 1607 |
|
| 1608 |
|
| 1609 | deactivate_mm(tsk, mm);
|
| 1610 |
|
| 1611 | |
| 1612 | * Signal userspace if we're not exiting with a core dump
|
| 1613 | * because we want to leave the value intact for debugging
|
| 1614 | * purposes.
|
| 1615 |
|
| 1616 | if (tsk->clear_child_tid) {
|
| 1617 | if (atomic_read(&mm->mm_users) > 1) {
|
| 1618 | |
| 1619 | * We don't check the error code - if userspace has
|
| 1620 | * not set up a proper pointer then tough luck.
|
| 1621 |
|
| 1622 | put_user(0, tsk->clear_child_tid);
|
| 1623 | do_futex(tsk->clear_child_tid, FUTEX_WAKE,
|
| 1624 | 1, NULL, NULL, 0, 0);
|
| 1625 | }
|
| 1626 | tsk->clear_child_tid = NULL;
|
| 1627 | }
|
| 1628 |
|
| 1629 | |
| 1630 | * All done, finally we can wake up parent and return this mm to him.
|
| 1631 | * Also kthread_stop() uses this completion for synchronization.
|
| 1632 |
|
| 1633 | if (tsk->vfork_done)
|
| 1634 | complete_vfork_done(tsk);
|
| 1635 | }
|
| 1636 |
|
| 1637 | void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm)
|
| 1638 | {
|
| 1639 | futex_exit_release(tsk);
|
| 1640 | mm_release(tsk, mm);
|
| 1641 | }
|
| 1642 |
|
| 1643 | void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm)
|
| 1644 | {
|
| 1645 | futex_exec_release(tsk);
|
| 1646 | mm_release(tsk, mm);
|
| 1647 | }
|
| 1648 |
|
| 1649 | |
| 1650 | * dup_mm() - duplicates an existing mm structure
|
| 1651 | * @tsk: the task_struct with which the new mm will be associated.
|
| 1652 | * @oldmm: the mm to duplicate.
|
| 1653 | *
|
| 1654 | * Allocates a new mm structure and duplicates the provided @oldmm structure
|
| 1655 | * content into it.
|
| 1656 | *
|
| 1657 | * Return: the duplicated mm or NULL on failure.
|
| 1658 |
|
| 1659 | static struct mm_struct *dup_mm(struct task_struct *tsk,
|
| 1660 | struct mm_struct *oldmm)
|
| 1661 | {
|
| 1662 | struct mm_struct *mm;
|
| 1663 | int err;
|
| 1664 |
|
| 1665 | mm = allocate_mm();
|
| 1666 | if (!mm)
|
| 1667 | goto fail_nomem;
|
| 1668 |
|
| 1669 | memcpy(mm, oldmm, sizeof(*mm));
|
| 1670 |
|
| 1671 | if (!mm_init(mm, tsk, mm->user_ns))
|
| 1672 | goto fail_nomem;
|
| 1673 |
|
| 1674 | err = dup_mmap(mm, oldmm);
|
| 1675 | if (err)
|
| 1676 | goto free_pt;
|
| 1677 |
|
| 1678 | mm->hiwater_rss = get_mm_rss(mm);
|
| 1679 | mm->hiwater_vm = mm->total_vm;
|
| 1680 |
|
| 1681 | if (mm->binfmt && !try_module_get(mm->binfmt->module))
|
| 1682 | goto free_pt;
|
| 1683 |
|
| 1684 | return mm;
|
| 1685 |
|
| 1686 | free_pt:
|
| 1687 |
|
| 1688 | mm->binfmt = NULL;
|
| 1689 | mm_init_owner(mm, NULL);
|
| 1690 | mmput(mm);
|
| 1691 |
|
| 1692 | fail_nomem:
|
| 1693 | return NULL;
|
| 1694 | }
|
| 1695 |
|
| 1696 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
|
| 1697 | {
|
| 1698 | struct mm_struct *mm, *oldmm;
|
| 1699 |
|
| 1700 | tsk->min_flt = tsk->maj_flt = 0;
|
| 1701 | tsk->nvcsw = tsk->nivcsw = 0;
|
| 1702 | #ifdef CONFIG_DETECT_HUNG_TASK
|
| 1703 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
|
| 1704 | tsk->last_switch_time = 0;
|
| 1705 | #endif
|
| 1706 |
|
| 1707 | tsk->mm = NULL;
|
| 1708 | tsk->active_mm = NULL;
|
| 1709 |
|
| 1710 | |
| 1711 | * Are we cloning a kernel thread?
|
| 1712 | *
|
| 1713 | * We need to steal a active VM for that..
|
| 1714 |
|
| 1715 | oldmm = current->mm;
|
| 1716 | if (!oldmm)
|
| 1717 | return 0;
|
| 1718 |
|
| 1719 | if (clone_flags & CLONE_VM) {
|
| 1720 | mmget(oldmm);
|
| 1721 | mm = oldmm;
|
| 1722 | } else {
|
| 1723 | mm = dup_mm(tsk, current->mm);
|
| 1724 | if (!mm)
|
| 1725 | return -ENOMEM;
|
| 1726 | }
|
| 1727 |
|
| 1728 | tsk->mm = mm;
|
| 1729 | tsk->active_mm = mm;
|
| 1730 | sched_mm_cid_fork(tsk);
|
| 1731 | return 0;
|
| 1732 | }
|
| 1733 |
|
| 1734 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
|
| 1735 | {
|
| 1736 | struct fs_struct *fs = current->fs;
|
| 1737 | if (clone_flags & CLONE_FS) {
|
| 1738 |
|
| 1739 | spin_lock(&fs->lock);
|
| 1740 |
|
| 1741 | if (fs->in_exec) {
|
| 1742 | spin_unlock(&fs->lock);
|
| 1743 | return -EAGAIN;
|
| 1744 | }
|
| 1745 | fs->users++;
|
| 1746 | spin_unlock(&fs->lock);
|
| 1747 | return 0;
|
| 1748 | }
|
| 1749 | tsk->fs = copy_fs_struct(fs);
|
| 1750 | if (!tsk->fs)
|
| 1751 | return -ENOMEM;
|
| 1752 | return 0;
|
| 1753 | }
|
| 1754 |
|
| 1755 | static int copy_files(unsigned long clone_flags, struct task_struct *tsk,
|
| 1756 | int no_files)
|
| 1757 | {
|
| 1758 | struct files_struct *oldf, *newf;
|
| 1759 |
|
| 1760 | |
| 1761 | * A background process may not have any files ...
|
| 1762 |
|
| 1763 | oldf = current->files;
|
| 1764 | if (!oldf)
|
| 1765 | return 0;
|
| 1766 |
|
| 1767 | if (no_files) {
|
| 1768 | tsk->files = NULL;
|
| 1769 | return 0;
|
| 1770 | }
|
| 1771 |
|
| 1772 | if (clone_flags & CLONE_FILES) {
|
| 1773 | atomic_inc(&oldf->count);
|
| 1774 | return 0;
|
| 1775 | }
|
| 1776 |
|
| 1777 | newf = dup_fd(oldf, NULL);
|
| 1778 | if (IS_ERR(newf))
|
| 1779 | return PTR_ERR(newf);
|
| 1780 |
|
| 1781 | tsk->files = newf;
|
| 1782 | return 0;
|
| 1783 | }
|
| 1784 |
|
| 1785 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
|
| 1786 | {
|
| 1787 | struct sighand_struct *sig;
|
| 1788 |
|
| 1789 | if (clone_flags & CLONE_SIGHAND) {
|
| 1790 | refcount_inc(¤t->sighand->count);
|
| 1791 | return 0;
|
| 1792 | }
|
| 1793 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
|
| 1794 | RCU_INIT_POINTER(tsk->sighand, sig);
|
| 1795 | if (!sig)
|
| 1796 | return -ENOMEM;
|
| 1797 |
|
| 1798 | refcount_set(&sig->count, 1);
|
| 1799 | spin_lock_irq(¤t->sighand->siglock);
|
| 1800 | memcpy(sig->action, current->sighand->action, sizeof(sig->action));
|
| 1801 | spin_unlock_irq(¤t->sighand->siglock);
|
| 1802 |
|
| 1803 |
|
| 1804 | if (clone_flags & CLONE_CLEAR_SIGHAND)
|
| 1805 | flush_signal_handlers(tsk, 0);
|
| 1806 |
|
| 1807 | return 0;
|
| 1808 | }
|
| 1809 |
|
| 1810 | void __cleanup_sighand(struct sighand_struct *sighand)
|
| 1811 | {
|
| 1812 | if (refcount_dec_and_test(&sighand->count)) {
|
| 1813 | signalfd_cleanup(sighand);
|
| 1814 | |
| 1815 | * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it
|
| 1816 | * without an RCU grace period, see __lock_task_sighand().
|
| 1817 |
|
| 1818 | kmem_cache_free(sighand_cachep, sighand);
|
| 1819 | }
|
| 1820 | }
|
| 1821 |
|
| 1822 | |
| 1823 | * Initialize POSIX timer handling for a thread group.
|
| 1824 |
|
| 1825 | static void posix_cpu_timers_init_group(struct signal_struct *sig)
|
| 1826 | {
|
| 1827 | struct posix_cputimers *pct = &sig->posix_cputimers;
|
| 1828 | unsigned long cpu_limit;
|
| 1829 |
|
| 1830 | cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
|
| 1831 | posix_cputimers_group_init(pct, cpu_limit);
|
| 1832 | }
|
| 1833 |
|
| 1834 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
|
| 1835 | {
|
| 1836 | struct signal_struct *sig;
|
| 1837 |
|
| 1838 | if (clone_flags & CLONE_THREAD)
|
| 1839 | return 0;
|
| 1840 |
|
| 1841 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL);
|
| 1842 | tsk->signal = sig;
|
| 1843 | if (!sig)
|
| 1844 | return -ENOMEM;
|
| 1845 |
|
| 1846 | sig->nr_threads = 1;
|
| 1847 | sig->quick_threads = 1;
|
| 1848 | atomic_set(&sig->live, 1);
|
| 1849 | refcount_set(&sig->sigcnt, 1);
|
| 1850 |
|
| 1851 |
|
| 1852 | sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
|
| 1853 | tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head);
|
| 1854 |
|
| 1855 | init_waitqueue_head(&sig->wait_chldexit);
|
| 1856 | sig->curr_target = tsk;
|
| 1857 | init_sigpending(&sig->shared_pending);
|
| 1858 | INIT_HLIST_HEAD(&sig->multiprocess);
|
| 1859 | seqlock_init(&sig->stats_lock);
|
| 1860 | prev_cputime_init(&sig->prev_cputime);
|
| 1861 |
|
| 1862 | #ifdef CONFIG_POSIX_TIMERS
|
| 1863 | INIT_HLIST_HEAD(&sig->posix_timers);
|
| 1864 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
|
| 1865 | sig->real_timer.function = it_real_fn;
|
| 1866 | #endif
|
| 1867 |
|
| 1868 | task_lock(current->group_leader);
|
| 1869 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
|
| 1870 | task_unlock(current->group_leader);
|
| 1871 |
|
| 1872 | posix_cpu_timers_init_group(sig);
|
| 1873 |
|
| 1874 | tty_audit_fork(sig);
|
| 1875 | sched_autogroup_fork(sig);
|
| 1876 |
|
| 1877 | sig->oom_score_adj = current->signal->oom_score_adj;
|
| 1878 | sig->oom_score_adj_min = current->signal->oom_score_adj_min;
|
| 1879 |
|
| 1880 | mutex_init(&sig->cred_guard_mutex);
|
| 1881 | init_rwsem(&sig->exec_update_lock);
|
| 1882 |
|
| 1883 | return 0;
|
| 1884 | }
|
| 1885 |
|
| 1886 | static void copy_seccomp(struct task_struct *p)
|
| 1887 | {
|
| 1888 | #ifdef CONFIG_SECCOMP
|
| 1889 | |
| 1890 | * Must be called with sighand->lock held, which is common to
|
| 1891 | * all threads in the group. Holding cred_guard_mutex is not
|
| 1892 | * needed because this new task is not yet running and cannot
|
| 1893 | * be racing exec.
|
| 1894 |
|
| 1895 | assert_spin_locked(¤t->sighand->siglock);
|
| 1896 |
|
| 1897 |
|
| 1898 | get_seccomp_filter(current);
|
| 1899 | p->seccomp = current->seccomp;
|
| 1900 |
|
| 1901 | |
| 1902 | * Explicitly enable no_new_privs here in case it got set
|
| 1903 | * between the task_struct being duplicated and holding the
|
| 1904 | * sighand lock. The seccomp state and nnp must be in sync.
|
| 1905 |
|
| 1906 | if (task_no_new_privs(current))
|
| 1907 | task_set_no_new_privs(p);
|
| 1908 |
|
| 1909 | |
| 1910 | * If the parent gained a seccomp mode after copying thread
|
| 1911 | * flags and between before we held the sighand lock, we have
|
| 1912 | * to manually enable the seccomp thread flag here.
|
| 1913 |
|
| 1914 | if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
|
| 1915 | set_task_syscall_work(p, SECCOMP);
|
| 1916 | #endif
|
| 1917 | }
|
| 1918 |
|
| 1919 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
|
| 1920 | {
|
| 1921 | current->clear_child_tid = tidptr;
|
| 1922 |
|
| 1923 | return task_pid_vnr(current);
|
| 1924 | }
|
| 1925 |
|
| 1926 | static void rt_mutex_init_task(struct task_struct *p)
|
| 1927 | {
|
| 1928 | raw_spin_lock_init(&p->pi_lock);
|
| 1929 | #ifdef CONFIG_RT_MUTEXES
|
| 1930 | p->pi_waiters = RB_ROOT_CACHED;
|
| 1931 | p->pi_top_task = NULL;
|
| 1932 | p->pi_blocked_on = NULL;
|
| 1933 | #endif
|
| 1934 | }
|
| 1935 |
|
| 1936 | static inline void init_task_pid_links(struct task_struct *task)
|
| 1937 | {
|
| 1938 | enum pid_type type;
|
| 1939 |
|
| 1940 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type)
|
| 1941 | INIT_HLIST_NODE(&task->pid_links[type]);
|
| 1942 | }
|
| 1943 |
|
| 1944 | static inline void
|
| 1945 | init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid)
|
| 1946 | {
|
| 1947 | if (type == PIDTYPE_PID)
|
| 1948 | task->thread_pid = pid;
|
| 1949 | else
|
| 1950 | task->signal->pids[type] = pid;
|
| 1951 | }
|
| 1952 |
|
| 1953 | static inline void rcu_copy_process(struct task_struct *p)
|
| 1954 | {
|
| 1955 | #ifdef CONFIG_PREEMPT_RCU
|
| 1956 | p->rcu_read_lock_nesting = 0;
|
| 1957 | p->rcu_read_unlock_special.s = 0;
|
| 1958 | p->rcu_blocked_node = NULL;
|
| 1959 | INIT_LIST_HEAD(&p->rcu_node_entry);
|
| 1960 | #endif
|
| 1961 | #ifdef CONFIG_TASKS_RCU
|
| 1962 | p->rcu_tasks_holdout = false;
|
| 1963 | INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
|
| 1964 | p->rcu_tasks_idle_cpu = -1;
|
| 1965 | INIT_LIST_HEAD(&p->rcu_tasks_exit_list);
|
| 1966 | #endif
|
| 1967 | #ifdef CONFIG_TASKS_TRACE_RCU
|
| 1968 | p->trc_reader_nesting = 0;
|
| 1969 | p->trc_reader_special.s = 0;
|
| 1970 | INIT_LIST_HEAD(&p->trc_holdout_list);
|
| 1971 | INIT_LIST_HEAD(&p->trc_blkd_node);
|
| 1972 | #endif
|
| 1973 | }
|
| 1974 |
|
| 1975 | |
| 1976 | * __pidfd_prepare - allocate a new pidfd_file and reserve a pidfd
|
| 1977 | * @pid: the struct pid for which to create a pidfd
|
| 1978 | * @flags: flags of the new @pidfd
|
| 1979 | * @ret: Where to return the file for the pidfd.
|
| 1980 | *
|
| 1981 | * Allocate a new file that stashes @pid and reserve a new pidfd number in the
|
| 1982 | * caller's file descriptor table. The pidfd is reserved but not installed yet.
|
| 1983 | *
|
| 1984 | * The helper doesn't perform checks on @pid which makes it useful for pidfds
|
| 1985 | * created via CLONE_PIDFD where @pid has no task attached when the pidfd and
|
| 1986 | * pidfd file are prepared.
|
| 1987 | *
|
| 1988 | * If this function returns successfully the caller is responsible to either
|
| 1989 | * call fd_install() passing the returned pidfd and pidfd file as arguments in
|
| 1990 | * order to install the pidfd into its file descriptor table or they must use
|
| 1991 | * put_unused_fd() and fput() on the returned pidfd and pidfd file
|
| 1992 | * respectively.
|
| 1993 | *
|
| 1994 | * This function is useful when a pidfd must already be reserved but there
|
| 1995 | * might still be points of failure afterwards and the caller wants to ensure
|
| 1996 | * that no pidfd is leaked into its file descriptor table.
|
| 1997 | *
|
| 1998 | * Return: On success, a reserved pidfd is returned from the function and a new
|
| 1999 | * pidfd file is returned in the last argument to the function. On
|
| 2000 | * error, a negative error code is returned from the function and the
|
| 2001 | * last argument remains unchanged.
|
| 2002 |
|
| 2003 | static int __pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret)
|
| 2004 | {
|
| 2005 | int pidfd;
|
| 2006 | struct file *pidfd_file;
|
| 2007 |
|
| 2008 | pidfd = get_unused_fd_flags(O_CLOEXEC);
|
| 2009 | if (pidfd < 0)
|
| 2010 | return pidfd;
|
| 2011 |
|
| 2012 | pidfd_file = pidfs_alloc_file(pid, flags | O_RDWR);
|
| 2013 | if (IS_ERR(pidfd_file)) {
|
| 2014 | put_unused_fd(pidfd);
|
| 2015 | return PTR_ERR(pidfd_file);
|
| 2016 | }
|
| 2017 | |
| 2018 | * anon_inode_getfile() ignores everything outside of the
|
| 2019 | * O_ACCMODE | O_NONBLOCK mask, set PIDFD_THREAD manually.
|
| 2020 |
|
| 2021 | pidfd_file->f_flags |= (flags & PIDFD_THREAD);
|
| 2022 | *ret = pidfd_file;
|
| 2023 | return pidfd;
|
| 2024 | }
|
| 2025 |
|
| 2026 | |
| 2027 | * pidfd_prepare - allocate a new pidfd_file and reserve a pidfd
|
| 2028 | * @pid: the struct pid for which to create a pidfd
|
| 2029 | * @flags: flags of the new @pidfd
|
| 2030 | * @ret: Where to return the pidfd.
|
| 2031 | *
|
| 2032 | * Allocate a new file that stashes @pid and reserve a new pidfd number in the
|
| 2033 | * caller's file descriptor table. The pidfd is reserved but not installed yet.
|
| 2034 | *
|
| 2035 | * The helper verifies that @pid is still in use, without PIDFD_THREAD the
|
| 2036 | * task identified by @pid must be a thread-group leader.
|
| 2037 | *
|
| 2038 | * If this function returns successfully the caller is responsible to either
|
| 2039 | * call fd_install() passing the returned pidfd and pidfd file as arguments in
|
| 2040 | * order to install the pidfd into its file descriptor table or they must use
|
| 2041 | * put_unused_fd() and fput() on the returned pidfd and pidfd file
|
| 2042 | * respectively.
|
| 2043 | *
|
| 2044 | * This function is useful when a pidfd must already be reserved but there
|
| 2045 | * might still be points of failure afterwards and the caller wants to ensure
|
| 2046 | * that no pidfd is leaked into its file descriptor table.
|
| 2047 | *
|
| 2048 | * Return: On success, a reserved pidfd is returned from the function and a new
|
| 2049 | * pidfd file is returned in the last argument to the function. On
|
| 2050 | * error, a negative error code is returned from the function and the
|
| 2051 | * last argument remains unchanged.
|
| 2052 |
|
| 2053 | int pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret)
|
| 2054 | {
|
| 2055 | bool thread = flags & PIDFD_THREAD;
|
| 2056 |
|
| 2057 | if (!pid || !pid_has_task(pid, thread ? PIDTYPE_PID : PIDTYPE_TGID))
|
| 2058 | return -EINVAL;
|
| 2059 |
|
| 2060 | return __pidfd_prepare(pid, flags, ret);
|
| 2061 | }
|
| 2062 |
|
| 2063 | static void __delayed_free_task(struct rcu_head *rhp)
|
| 2064 | {
|
| 2065 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
|
| 2066 |
|
| 2067 | free_task(tsk);
|
| 2068 | }
|
| 2069 |
|
| 2070 | static __always_inline void delayed_free_task(struct task_struct *tsk)
|
| 2071 | {
|
| 2072 | if (IS_ENABLED(CONFIG_MEMCG))
|
| 2073 | call_rcu(&tsk->rcu, __delayed_free_task);
|
| 2074 | else
|
| 2075 | free_task(tsk);
|
| 2076 | }
|
| 2077 |
|
| 2078 | static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk)
|
| 2079 | {
|
| 2080 |
|
| 2081 | if (!tsk->mm)
|
| 2082 | return;
|
| 2083 |
|
| 2084 |
|
| 2085 | if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM)
|
| 2086 | return;
|
| 2087 |
|
| 2088 |
|
| 2089 | mutex_lock(&oom_adj_mutex);
|
| 2090 | set_bit(MMF_MULTIPROCESS, &tsk->mm->flags);
|
| 2091 |
|
| 2092 | tsk->signal->oom_score_adj = current->signal->oom_score_adj;
|
| 2093 | tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min;
|
| 2094 | mutex_unlock(&oom_adj_mutex);
|
| 2095 | }
|
| 2096 |
|
| 2097 | #ifdef CONFIG_RV
|
| 2098 | static void rv_task_fork(struct task_struct *p)
|
| 2099 | {
|
| 2100 | int i;
|
| 2101 |
|
| 2102 | for (i = 0; i < RV_PER_TASK_MONITORS; i++)
|
| 2103 | p->rv[i].da_mon.monitoring = false;
|
| 2104 | }
|
| 2105 | #else
|
| 2106 | #define rv_task_fork(p) do {} while (0)
|
| 2107 | #endif
|
| 2108 |
|
| 2109 | |
| 2110 | * This creates a new process as a copy of the old one,
|
| 2111 | * but does not actually start it yet.
|
| 2112 | *
|
| 2113 | * It copies the registers, and all the appropriate
|
| 2114 | * parts of the process environment (as per the clone
|
| 2115 | * flags). The actual kick-off is left to the caller.
|
| 2116 |
|
| 2117 | __latent_entropy struct task_struct *copy_process(
|
| 2118 | struct pid *pid,
|
| 2119 | int trace,
|
| 2120 | int node,
|
| 2121 | struct kernel_clone_args *args)
|
| 2122 | {
|
| 2123 | int pidfd = -1, retval;
|
| 2124 | struct task_struct *p;
|
| 2125 | struct multiprocess_signals delayed;
|
| 2126 | struct file *pidfile = NULL;
|
| 2127 | const u64 clone_flags = args->flags;
|
| 2128 | struct nsproxy *nsp = current->nsproxy;
|
| 2129 |
|
| 2130 | |
| 2131 | * Don't allow sharing the root directory with processes in a different
|
| 2132 | * namespace
|
| 2133 |
|
| 2134 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
|
| 2135 | return ERR_PTR(-EINVAL);
|
| 2136 |
|
| 2137 | if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
|
| 2138 | return ERR_PTR(-EINVAL);
|
| 2139 |
|
| 2140 | |
| 2141 | * Thread groups must share signals as well, and detached threads
|
| 2142 | * can only be started up within the thread group.
|
| 2143 |
|
| 2144 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
|
| 2145 | return ERR_PTR(-EINVAL);
|
| 2146 |
|
| 2147 | |
| 2148 | * Shared signal handlers imply shared VM. By way of the above,
|
| 2149 | * thread groups also imply shared VM. Blocking this case allows
|
| 2150 | * for various simplifications in other code.
|
| 2151 |
|
| 2152 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
|
| 2153 | return ERR_PTR(-EINVAL);
|
| 2154 |
|
| 2155 | |
| 2156 | * Siblings of global init remain as zombies on exit since they are
|
| 2157 | * not reaped by their parent (swapper). To solve this and to avoid
|
| 2158 | * multi-rooted process trees, prevent global and container-inits
|
| 2159 | * from creating siblings.
|
| 2160 |
|
| 2161 | if ((clone_flags & CLONE_PARENT) &&
|
| 2162 | current->signal->flags & SIGNAL_UNKILLABLE)
|
| 2163 | return ERR_PTR(-EINVAL);
|
| 2164 |
|
| 2165 | |
| 2166 | * If the new process will be in a different pid or user namespace
|
| 2167 | * do not allow it to share a thread group with the forking task.
|
| 2168 |
|
| 2169 | if (clone_flags & CLONE_THREAD) {
|
| 2170 | if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) ||
|
| 2171 | (task_active_pid_ns(current) != nsp->pid_ns_for_children))
|
| 2172 | return ERR_PTR(-EINVAL);
|
| 2173 | }
|
| 2174 |
|
| 2175 | if (clone_flags & CLONE_PIDFD) {
|
| 2176 | |
| 2177 | * - CLONE_DETACHED is blocked so that we can potentially
|
| 2178 | * reuse it later for CLONE_PIDFD.
|
| 2179 |
|
| 2180 | if (clone_flags & CLONE_DETACHED)
|
| 2181 | return ERR_PTR(-EINVAL);
|
| 2182 | }
|
| 2183 |
|
| 2184 | |
| 2185 | * Force any signals received before this point to be delivered
|
| 2186 | * before the fork happens. Collect up signals sent to multiple
|
| 2187 | * processes that happen during the fork and delay them so that
|
| 2188 | * they appear to happen after the fork.
|
| 2189 |
|
| 2190 | sigemptyset(&delayed.signal);
|
| 2191 | INIT_HLIST_NODE(&delayed.node);
|
| 2192 |
|
| 2193 | spin_lock_irq(¤t->sighand->siglock);
|
| 2194 | if (!(clone_flags & CLONE_THREAD))
|
| 2195 | hlist_add_head(&delayed.node, ¤t->signal->multiprocess);
|
| 2196 | recalc_sigpending();
|
| 2197 | spin_unlock_irq(¤t->sighand->siglock);
|
| 2198 | retval = -ERESTARTNOINTR;
|
| 2199 | if (task_sigpending(current))
|
| 2200 | goto fork_out;
|
| 2201 |
|
| 2202 | retval = -ENOMEM;
|
| 2203 | p = dup_task_struct(current, node);
|
| 2204 | if (!p)
|
| 2205 | goto fork_out;
|
| 2206 | p->flags &= ~PF_KTHREAD;
|
| 2207 | if (args->kthread)
|
| 2208 | p->flags |= PF_KTHREAD;
|
| 2209 | if (args->user_worker) {
|
| 2210 | |
| 2211 | * Mark us a user worker, and block any signal that isn't
|
| 2212 | * fatal or STOP
|
| 2213 |
|
| 2214 | p->flags |= PF_USER_WORKER;
|
| 2215 | siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
| 2216 | }
|
| 2217 | if (args->io_thread)
|
| 2218 | p->flags |= PF_IO_WORKER;
|
| 2219 |
|
| 2220 | if (args->name)
|
| 2221 | strscpy_pad(p->comm, args->name, sizeof(p->comm));
|
| 2222 |
|
| 2223 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL;
|
| 2224 | |
| 2225 | * Clear TID on mm_release()?
|
| 2226 |
|
| 2227 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL;
|
| 2228 |
|
| 2229 | ftrace_graph_init_task(p);
|
| 2230 |
|
| 2231 | rt_mutex_init_task(p);
|
| 2232 |
|
| 2233 | lockdep_assert_irqs_enabled();
|
| 2234 | #ifdef CONFIG_PROVE_LOCKING
|
| 2235 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
|
| 2236 | #endif
|
| 2237 | retval = copy_creds(p, clone_flags);
|
| 2238 | if (retval < 0)
|
| 2239 | goto bad_fork_free;
|
| 2240 |
|
| 2241 | retval = -EAGAIN;
|
| 2242 | if (is_rlimit_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) {
|
| 2243 | if (p->real_cred->user != INIT_USER &&
|
| 2244 | !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
|
| 2245 | goto bad_fork_cleanup_count;
|
| 2246 | }
|
| 2247 | current->flags &= ~PF_NPROC_EXCEEDED;
|
| 2248 |
|
| 2249 | |
| 2250 | * If multiple threads are within copy_process(), then this check
|
| 2251 | * triggers too late. This doesn't hurt, the check is only there
|
| 2252 | * to stop root fork bombs.
|
| 2253 |
|
| 2254 | retval = -EAGAIN;
|
| 2255 | if (data_race(nr_threads >= max_threads))
|
| 2256 | goto bad_fork_cleanup_count;
|
| 2257 |
|
| 2258 | delayacct_tsk_init(p);
|
| 2259 | p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY);
|
| 2260 | p->flags |= PF_FORKNOEXEC;
|
| 2261 | INIT_LIST_HEAD(&p->children);
|
| 2262 | INIT_LIST_HEAD(&p->sibling);
|
| 2263 | rcu_copy_process(p);
|
| 2264 | p->vfork_done = NULL;
|
| 2265 | spin_lock_init(&p->alloc_lock);
|
| 2266 |
|
| 2267 | init_sigpending(&p->pending);
|
| 2268 |
|
| 2269 | p->utime = p->stime = p->gtime = 0;
|
| 2270 | #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
|
| 2271 | p->utimescaled = p->stimescaled = 0;
|
| 2272 | #endif
|
| 2273 | prev_cputime_init(&p->prev_cputime);
|
| 2274 |
|
| 2275 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
|
| 2276 | seqcount_init(&p->vtime.seqcount);
|
| 2277 | p->vtime.starttime = 0;
|
| 2278 | p->vtime.state = VTIME_INACTIVE;
|
| 2279 | #endif
|
| 2280 |
|
| 2281 | #ifdef CONFIG_IO_URING
|
| 2282 | p->io_uring = NULL;
|
| 2283 | #endif
|
| 2284 |
|
| 2285 | p->default_timer_slack_ns = current->timer_slack_ns;
|
| 2286 |
|
| 2287 | #ifdef CONFIG_PSI
|
| 2288 | p->psi_flags = 0;
|
| 2289 | #endif
|
| 2290 |
|
| 2291 | task_io_accounting_init(&p->ioac);
|
| 2292 | acct_clear_integrals(p);
|
| 2293 |
|
| 2294 | posix_cputimers_init(&p->posix_cputimers);
|
| 2295 |
|
| 2296 | p->io_context = NULL;
|
| 2297 | audit_set_context(p, NULL);
|
| 2298 | cgroup_fork(p);
|
| 2299 | if (args->kthread) {
|
| 2300 | if (!set_kthread_struct(p))
|
| 2301 | goto bad_fork_cleanup_delayacct;
|
| 2302 | }
|
| 2303 | #ifdef CONFIG_NUMA
|
| 2304 | p->mempolicy = mpol_dup(p->mempolicy);
|
| 2305 | if (IS_ERR(p->mempolicy)) {
|
| 2306 | retval = PTR_ERR(p->mempolicy);
|
| 2307 | p->mempolicy = NULL;
|
| 2308 | goto bad_fork_cleanup_delayacct;
|
| 2309 | }
|
| 2310 | #endif
|
| 2311 | #ifdef CONFIG_CPUSETS
|
| 2312 | p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
|
| 2313 | seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock);
|
| 2314 | #endif
|
| 2315 | #ifdef CONFIG_TRACE_IRQFLAGS
|
| 2316 | memset(&p->irqtrace, 0, sizeof(p->irqtrace));
|
| 2317 | p->irqtrace.hardirq_disable_ip = _THIS_IP_;
|
| 2318 | p->irqtrace.softirq_enable_ip = _THIS_IP_;
|
| 2319 | p->softirqs_enabled = 1;
|
| 2320 | p->softirq_context = 0;
|
| 2321 | #endif
|
| 2322 |
|
| 2323 | p->pagefault_disabled = 0;
|
| 2324 |
|
| 2325 | #ifdef CONFIG_LOCKDEP
|
| 2326 | lockdep_init_task(p);
|
| 2327 | #endif
|
| 2328 |
|
| 2329 | #ifdef CONFIG_DEBUG_MUTEXES
|
| 2330 | p->blocked_on = NULL;
|
| 2331 | #endif
|
| 2332 | #ifdef CONFIG_BCACHE
|
| 2333 | p->sequential_io = 0;
|
| 2334 | p->sequential_io_avg = 0;
|
| 2335 | #endif
|
| 2336 | #ifdef CONFIG_BPF_SYSCALL
|
| 2337 | RCU_INIT_POINTER(p->bpf_storage, NULL);
|
| 2338 | p->bpf_ctx = NULL;
|
| 2339 | #endif
|
| 2340 |
|
| 2341 |
|
| 2342 | retval = sched_fork(clone_flags, p);
|
| 2343 | if (retval)
|
| 2344 | goto bad_fork_cleanup_policy;
|
| 2345 |
|
| 2346 | retval = perf_event_init_task(p, clone_flags);
|
| 2347 | if (retval)
|
| 2348 | goto bad_fork_sched_cancel_fork;
|
| 2349 | retval = audit_alloc(p);
|
| 2350 | if (retval)
|
| 2351 | goto bad_fork_cleanup_perf;
|
| 2352 |
|
| 2353 | shm_init_task(p);
|
| 2354 | retval = security_task_alloc(p, clone_flags);
|
| 2355 | if (retval)
|
| 2356 | goto bad_fork_cleanup_audit;
|
| 2357 | retval = copy_semundo(clone_flags, p);
|
| 2358 | if (retval)
|
| 2359 | goto bad_fork_cleanup_security;
|
| 2360 | retval = copy_files(clone_flags, p, args->no_files);
|
| 2361 | if (retval)
|
| 2362 | goto bad_fork_cleanup_semundo;
|
| 2363 | retval = copy_fs(clone_flags, p);
|
| 2364 | if (retval)
|
| 2365 | goto bad_fork_cleanup_files;
|
| 2366 | retval = copy_sighand(clone_flags, p);
|
| 2367 | if (retval)
|
| 2368 | goto bad_fork_cleanup_fs;
|
| 2369 | retval = copy_signal(clone_flags, p);
|
| 2370 | if (retval)
|
| 2371 | goto bad_fork_cleanup_sighand;
|
| 2372 | retval = copy_mm(clone_flags, p);
|
| 2373 | if (retval)
|
| 2374 | goto bad_fork_cleanup_signal;
|
| 2375 | retval = copy_namespaces(clone_flags, p);
|
| 2376 | if (retval)
|
| 2377 | goto bad_fork_cleanup_mm;
|
| 2378 | retval = copy_io(clone_flags, p);
|
| 2379 | if (retval)
|
| 2380 | goto bad_fork_cleanup_namespaces;
|
| 2381 | retval = copy_thread(p, args);
|
| 2382 | if (retval)
|
| 2383 | goto bad_fork_cleanup_io;
|
| 2384 |
|
| 2385 | stackleak_task_init(p);
|
| 2386 |
|
| 2387 | if (pid != &init_struct_pid) {
|
| 2388 | pid = alloc_pid(p->nsproxy->pid_ns_for_children, args->set_tid,
|
| 2389 | args->set_tid_size);
|
| 2390 | if (IS_ERR(pid)) {
|
| 2391 | retval = PTR_ERR(pid);
|
| 2392 | goto bad_fork_cleanup_thread;
|
| 2393 | }
|
| 2394 | }
|
| 2395 |
|
| 2396 | |
| 2397 | * This has to happen after we've potentially unshared the file
|
| 2398 | * descriptor table (so that the pidfd doesn't leak into the child
|
| 2399 | * if the fd table isn't shared).
|
| 2400 |
|
| 2401 | if (clone_flags & CLONE_PIDFD) {
|
| 2402 | int flags = (clone_flags & CLONE_THREAD) ? PIDFD_THREAD : 0;
|
| 2403 |
|
| 2404 |
|
| 2405 | retval = __pidfd_prepare(pid, flags, &pidfile);
|
| 2406 | if (retval < 0)
|
| 2407 | goto bad_fork_free_pid;
|
| 2408 | pidfd = retval;
|
| 2409 |
|
| 2410 | retval = put_user(pidfd, args->pidfd);
|
| 2411 | if (retval)
|
| 2412 | goto bad_fork_put_pidfd;
|
| 2413 | }
|
| 2414 |
|
| 2415 | #ifdef CONFIG_BLOCK
|
| 2416 | p->plug = NULL;
|
| 2417 | #endif
|
| 2418 | futex_init_task(p);
|
| 2419 |
|
| 2420 | |
| 2421 | * sigaltstack should be cleared when sharing the same VM
|
| 2422 |
|
| 2423 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
|
| 2424 | sas_ss_reset(p);
|
| 2425 |
|
| 2426 | |
| 2427 | * Syscall tracing and stepping should be turned off in the
|
| 2428 | * child regardless of CLONE_PTRACE.
|
| 2429 |
|
| 2430 | user_disable_single_step(p);
|
| 2431 | clear_task_syscall_work(p, SYSCALL_TRACE);
|
| 2432 | #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
|
| 2433 | clear_task_syscall_work(p, SYSCALL_EMU);
|
| 2434 | #endif
|
| 2435 | clear_tsk_latency_tracing(p);
|
| 2436 |
|
| 2437 |
|
| 2438 | p->pid = pid_nr(pid);
|
| 2439 | if (clone_flags & CLONE_THREAD) {
|
| 2440 | p->group_leader = current->group_leader;
|
| 2441 | p->tgid = current->tgid;
|
| 2442 | } else {
|
| 2443 | p->group_leader = p;
|
| 2444 | p->tgid = p->pid;
|
| 2445 | }
|
| 2446 |
|
| 2447 | p->nr_dirtied = 0;
|
| 2448 | p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
|
| 2449 | p->dirty_paused_when = 0;
|
| 2450 |
|
| 2451 | p->pdeath_signal = 0;
|
| 2452 | p->task_works = NULL;
|
| 2453 | clear_posix_cputimers_work(p);
|
| 2454 |
|
| 2455 | #ifdef CONFIG_KRETPROBES
|
| 2456 | p->kretprobe_instances.first = NULL;
|
| 2457 | #endif
|
| 2458 | #ifdef CONFIG_RETHOOK
|
| 2459 | p->rethooks.first = NULL;
|
| 2460 | #endif
|
| 2461 |
|
| 2462 | |
| 2463 | * Ensure that the cgroup subsystem policies allow the new process to be
|
| 2464 | * forked. It should be noted that the new process's css_set can be changed
|
| 2465 | * between here and cgroup_post_fork() if an organisation operation is in
|
| 2466 | * progress.
|
| 2467 |
|
| 2468 | retval = cgroup_can_fork(p, args);
|
| 2469 | if (retval)
|
| 2470 | goto bad_fork_put_pidfd;
|
| 2471 |
|
| 2472 | |
| 2473 | * Now that the cgroups are pinned, re-clone the parent cgroup and put
|
| 2474 | * the new task on the correct runqueue. All this *before* the task
|
| 2475 | * becomes visible.
|
| 2476 | *
|
| 2477 | * This isn't part of ->can_fork() because while the re-cloning is
|
| 2478 | * cgroup specific, it unconditionally needs to place the task on a
|
| 2479 | * runqueue.
|
| 2480 |
|
| 2481 | retval = sched_cgroup_fork(p, args);
|
| 2482 | if (retval)
|
| 2483 | goto bad_fork_cancel_cgroup;
|
| 2484 |
|
| 2485 | |
| 2486 | * From this point on we must avoid any synchronous user-space
|
| 2487 | * communication until we take the tasklist-lock. In particular, we do
|
| 2488 | * not want user-space to be able to predict the process start-time by
|
| 2489 | * stalling fork(2) after we recorded the start_time but before it is
|
| 2490 | * visible to the system.
|
| 2491 |
|
| 2492 |
|
| 2493 | p->start_time = ktime_get_ns();
|
| 2494 | p->start_boottime = ktime_get_boottime_ns();
|
| 2495 |
|
| 2496 | |
| 2497 | * Make it visible to the rest of the system, but dont wake it up yet.
|
| 2498 | * Need tasklist lock for parent etc handling!
|
| 2499 |
|
| 2500 | write_lock_irq(&tasklist_lock);
|
| 2501 |
|
| 2502 |
|
| 2503 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
|
| 2504 | p->real_parent = current->real_parent;
|
| 2505 | p->parent_exec_id = current->parent_exec_id;
|
| 2506 | if (clone_flags & CLONE_THREAD)
|
| 2507 | p->exit_signal = -1;
|
| 2508 | else
|
| 2509 | p->exit_signal = current->group_leader->exit_signal;
|
| 2510 | } else {
|
| 2511 | p->real_parent = current;
|
| 2512 | p->parent_exec_id = current->self_exec_id;
|
| 2513 | p->exit_signal = args->exit_signal;
|
| 2514 | }
|
| 2515 |
|
| 2516 | klp_copy_process(p);
|
| 2517 |
|
| 2518 | sched_core_fork(p);
|
| 2519 |
|
| 2520 | spin_lock(¤t->sighand->siglock);
|
| 2521 |
|
| 2522 | rv_task_fork(p);
|
| 2523 |
|
| 2524 | rseq_fork(p, clone_flags);
|
| 2525 |
|
| 2526 |
|
| 2527 | if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) {
|
| 2528 | retval = -ENOMEM;
|
| 2529 | goto bad_fork_core_free;
|
| 2530 | }
|
| 2531 |
|
| 2532 |
|
| 2533 | if (fatal_signal_pending(current)) {
|
| 2534 | retval = -EINTR;
|
| 2535 | goto bad_fork_core_free;
|
| 2536 | }
|
| 2537 |
|
| 2538 |
|
| 2539 |
|
| 2540 | |
| 2541 | * Copy seccomp details explicitly here, in case they were changed
|
| 2542 | * before holding sighand lock.
|
| 2543 |
|
| 2544 | copy_seccomp(p);
|
| 2545 |
|
| 2546 | init_task_pid_links(p);
|
| 2547 | if (likely(p->pid)) {
|
| 2548 | ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
|
| 2549 |
|
| 2550 | init_task_pid(p, PIDTYPE_PID, pid);
|
| 2551 | if (thread_group_leader(p)) {
|
| 2552 | init_task_pid(p, PIDTYPE_TGID, pid);
|
| 2553 | init_task_pid(p, PIDTYPE_PGID, task_pgrp(current));
|
| 2554 | init_task_pid(p, PIDTYPE_SID, task_session(current));
|
| 2555 |
|
| 2556 | if (is_child_reaper(pid)) {
|
| 2557 | ns_of_pid(pid)->child_reaper = p;
|
| 2558 | p->signal->flags |= SIGNAL_UNKILLABLE;
|
| 2559 | }
|
| 2560 | p->signal->shared_pending.signal = delayed.signal;
|
| 2561 | p->signal->tty = tty_kref_get(current->signal->tty);
|
| 2562 | |
| 2563 | * Inherit has_child_subreaper flag under the same
|
| 2564 | * tasklist_lock with adding child to the process tree
|
| 2565 | * for propagate_has_child_subreaper optimization.
|
| 2566 |
|
| 2567 | p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper ||
|
| 2568 | p->real_parent->signal->is_child_subreaper;
|
| 2569 | list_add_tail(&p->sibling, &p->real_parent->children);
|
| 2570 | list_add_tail_rcu(&p->tasks, &init_task.tasks);
|
| 2571 | attach_pid(p, PIDTYPE_TGID);
|
| 2572 | attach_pid(p, PIDTYPE_PGID);
|
| 2573 | attach_pid(p, PIDTYPE_SID);
|
| 2574 | __this_cpu_inc(process_counts);
|
| 2575 | } else {
|
| 2576 | current->signal->nr_threads++;
|
| 2577 | current->signal->quick_threads++;
|
| 2578 | atomic_inc(¤t->signal->live);
|
| 2579 | refcount_inc(¤t->signal->sigcnt);
|
| 2580 | task_join_group_stop(p);
|
| 2581 | list_add_tail_rcu(&p->thread_node,
|
| 2582 | &p->signal->thread_head);
|
| 2583 | }
|
| 2584 | attach_pid(p, PIDTYPE_PID);
|
| 2585 | nr_threads++;
|
| 2586 | }
|
| 2587 | total_forks++;
|
| 2588 | hlist_del_init(&delayed.node);
|
| 2589 | spin_unlock(¤t->sighand->siglock);
|
| 2590 | syscall_tracepoint_update(p);
|
| 2591 | write_unlock_irq(&tasklist_lock);
|
| 2592 |
|
| 2593 | if (pidfile)
|
| 2594 | fd_install(pidfd, pidfile);
|
| 2595 |
|
| 2596 | proc_fork_connector(p);
|
| 2597 | sched_post_fork(p);
|
| 2598 | cgroup_post_fork(p, args);
|
| 2599 | perf_event_fork(p);
|
| 2600 |
|
| 2601 | trace_task_newtask(p, clone_flags);
|
| 2602 | uprobe_copy_process(p, clone_flags);
|
| 2603 | user_events_fork(p, clone_flags);
|
| 2604 |
|
| 2605 | copy_oom_score_adj(clone_flags, p);
|
| 2606 |
|
| 2607 | return p;
|
| 2608 |
|
| 2609 | bad_fork_core_free:
|
| 2610 | sched_core_free(p);
|
| 2611 | spin_unlock(¤t->sighand->siglock);
|
| 2612 | write_unlock_irq(&tasklist_lock);
|
| 2613 | bad_fork_cancel_cgroup:
|
| 2614 | cgroup_cancel_fork(p, args);
|
| 2615 | bad_fork_put_pidfd:
|
| 2616 | if (clone_flags & CLONE_PIDFD) {
|
| 2617 | fput(pidfile);
|
| 2618 | put_unused_fd(pidfd);
|
| 2619 | }
|
| 2620 | bad_fork_free_pid:
|
| 2621 | if (pid != &init_struct_pid)
|
| 2622 | free_pid(pid);
|
| 2623 | bad_fork_cleanup_thread:
|
| 2624 | exit_thread(p);
|
| 2625 | bad_fork_cleanup_io:
|
| 2626 | if (p->io_context)
|
| 2627 | exit_io_context(p);
|
| 2628 | bad_fork_cleanup_namespaces:
|
| 2629 | exit_task_namespaces(p);
|
| 2630 | bad_fork_cleanup_mm:
|
| 2631 | if (p->mm) {
|
| 2632 | mm_clear_owner(p->mm, p);
|
| 2633 | mmput(p->mm);
|
| 2634 | }
|
| 2635 | bad_fork_cleanup_signal:
|
| 2636 | if (!(clone_flags & CLONE_THREAD))
|
| 2637 | free_signal_struct(p->signal);
|
| 2638 | bad_fork_cleanup_sighand:
|
| 2639 | __cleanup_sighand(p->sighand);
|
| 2640 | bad_fork_cleanup_fs:
|
| 2641 | exit_fs(p);
|
| 2642 | bad_fork_cleanup_files:
|
| 2643 | exit_files(p);
|
| 2644 | bad_fork_cleanup_semundo:
|
| 2645 | exit_sem(p);
|
| 2646 | bad_fork_cleanup_security:
|
| 2647 | security_task_free(p);
|
| 2648 | bad_fork_cleanup_audit:
|
| 2649 | audit_free(p);
|
| 2650 | bad_fork_cleanup_perf:
|
| 2651 | perf_event_free_task(p);
|
| 2652 | bad_fork_sched_cancel_fork:
|
| 2653 | sched_cancel_fork(p);
|
| 2654 | bad_fork_cleanup_policy:
|
| 2655 | lockdep_free_task(p);
|
| 2656 | #ifdef CONFIG_NUMA
|
| 2657 | mpol_put(p->mempolicy);
|
| 2658 | #endif
|
| 2659 | bad_fork_cleanup_delayacct:
|
| 2660 | delayacct_tsk_free(p);
|
| 2661 | bad_fork_cleanup_count:
|
| 2662 | dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
|
| 2663 | exit_creds(p);
|
| 2664 | bad_fork_free:
|
| 2665 | WRITE_ONCE(p->__state, TASK_DEAD);
|
| 2666 | exit_task_stack_account(p);
|
| 2667 | put_task_stack(p);
|
| 2668 | delayed_free_task(p);
|
| 2669 | fork_out:
|
| 2670 | spin_lock_irq(¤t->sighand->siglock);
|
| 2671 | hlist_del_init(&delayed.node);
|
| 2672 | spin_unlock_irq(¤t->sighand->siglock);
|
| 2673 | return ERR_PTR(retval);
|
| 2674 | }
|
| 2675 |
|
| 2676 | static inline void init_idle_pids(struct task_struct *idle)
|
| 2677 | {
|
| 2678 | enum pid_type type;
|
| 2679 |
|
| 2680 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
|
| 2681 | INIT_HLIST_NODE(&idle->pid_links[type]);
|
| 2682 | init_task_pid(idle, type, &init_struct_pid);
|
| 2683 | }
|
| 2684 | }
|
| 2685 |
|
| 2686 | static int idle_dummy(void *dummy)
|
| 2687 | {
|
| 2688 |
|
| 2689 | return 0;
|
| 2690 | }
|
| 2691 |
|
| 2692 | struct task_struct * __init fork_idle(int cpu)
|
| 2693 | {
|
| 2694 | struct task_struct *task;
|
| 2695 | struct kernel_clone_args args = {
|
| 2696 | .flags = CLONE_VM,
|
| 2697 | .fn = &idle_dummy,
|
| 2698 | .fn_arg = NULL,
|
| 2699 | .kthread = 1,
|
| 2700 | .idle = 1,
|
| 2701 | };
|
| 2702 |
|
| 2703 | task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args);
|
| 2704 | if (!IS_ERR(task)) {
|
| 2705 | init_idle_pids(task);
|
| 2706 | init_idle(task, cpu);
|
| 2707 | }
|
| 2708 |
|
| 2709 | return task;
|
| 2710 | }
|
| 2711 |
|
| 2712 | |
| 2713 | * This is like kernel_clone(), but shaved down and tailored to just
|
| 2714 | * creating io_uring workers. It returns a created task, or an error pointer.
|
| 2715 | * The returned task is inactive, and the caller must fire it up through
|
| 2716 | * wake_up_new_task(p). All signals are blocked in the created task.
|
| 2717 |
|
| 2718 | struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
|
| 2719 | {
|
| 2720 | unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|
|
| 2721 | CLONE_IO;
|
| 2722 | struct kernel_clone_args args = {
|
| 2723 | .flags = ((lower_32_bits(flags) | CLONE_VM |
|
| 2724 | CLONE_UNTRACED) & ~CSIGNAL),
|
| 2725 | .exit_signal = (lower_32_bits(flags) & CSIGNAL),
|
| 2726 | .fn = fn,
|
| 2727 | .fn_arg = arg,
|
| 2728 | .io_thread = 1,
|
| 2729 | .user_worker = 1,
|
| 2730 | };
|
| 2731 |
|
| 2732 | return copy_process(NULL, 0, node, &args);
|
| 2733 | }
|
| 2734 |
|
| 2735 | |
| 2736 | * Ok, this is the main fork-routine.
|
| 2737 | *
|
| 2738 | * It copies the process, and if successful kick-starts
|
| 2739 | * it and waits for it to finish using the VM if required.
|
| 2740 | *
|
| 2741 | * args->exit_signal is expected to be checked for sanity by the caller.
|
| 2742 |
|
| 2743 | pid_t kernel_clone(struct kernel_clone_args *args)
|
| 2744 | {
|
| 2745 | u64 clone_flags = args->flags;
|
| 2746 | struct completion vfork;
|
| 2747 | struct pid *pid;
|
| 2748 | struct task_struct *p;
|
| 2749 | int trace = 0;
|
| 2750 | pid_t nr;
|
| 2751 |
|
| 2752 | |
| 2753 | * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument
|
| 2754 | * to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are
|
| 2755 | * mutually exclusive. With clone3() CLONE_PIDFD has grown a separate
|
| 2756 | * field in struct clone_args and it still doesn't make sense to have
|
| 2757 | * them both point at the same memory location. Performing this check
|
| 2758 | * here has the advantage that we don't need to have a separate helper
|
| 2759 | * to check for legacy clone().
|
| 2760 |
|
| 2761 | if ((clone_flags & CLONE_PIDFD) &&
|
| 2762 | (clone_flags & CLONE_PARENT_SETTID) &&
|
| 2763 | (args->pidfd == args->parent_tid))
|
| 2764 | return -EINVAL;
|
| 2765 |
|
| 2766 | |
| 2767 | * Determine whether and which event to report to ptracer. When
|
| 2768 | * called from kernel_thread or CLONE_UNTRACED is explicitly
|
| 2769 | * requested, no event is reported; otherwise, report if the event
|
| 2770 | * for the type of forking is enabled.
|
| 2771 |
|
| 2772 | if (!(clone_flags & CLONE_UNTRACED)) {
|
| 2773 | if (clone_flags & CLONE_VFORK)
|
| 2774 | trace = PTRACE_EVENT_VFORK;
|
| 2775 | else if (args->exit_signal != SIGCHLD)
|
| 2776 | trace = PTRACE_EVENT_CLONE;
|
| 2777 | else
|
| 2778 | trace = PTRACE_EVENT_FORK;
|
| 2779 |
|
| 2780 | if (likely(!ptrace_event_enabled(current, trace)))
|
| 2781 | trace = 0;
|
| 2782 | }
|
| 2783 |
|
| 2784 | p = copy_process(NULL, trace, NUMA_NO_NODE, args);
|
| 2785 | add_latent_entropy();
|
| 2786 |
|
| 2787 | if (IS_ERR(p))
|
| 2788 | return PTR_ERR(p);
|
| 2789 |
|
| 2790 | |
| 2791 | * Do this prior waking up the new thread - the thread pointer
|
| 2792 | * might get invalid after that point, if the thread exits quickly.
|
| 2793 |
|
| 2794 | trace_sched_process_fork(current, p);
|
| 2795 |
|
| 2796 | pid = get_task_pid(p, PIDTYPE_PID);
|
| 2797 | nr = pid_vnr(pid);
|
| 2798 |
|
| 2799 | if (clone_flags & CLONE_PARENT_SETTID)
|
| 2800 | put_user(nr, args->parent_tid);
|
| 2801 |
|
| 2802 | if (clone_flags & CLONE_VFORK) {
|
| 2803 | p->vfork_done = &vfork;
|
| 2804 | init_completion(&vfork);
|
| 2805 | get_task_struct(p);
|
| 2806 | }
|
| 2807 |
|
| 2808 | if (IS_ENABLED(CONFIG_LRU_GEN_WALKS_MMU) && !(clone_flags & CLONE_VM)) {
|
| 2809 |
|
| 2810 | task_lock(p);
|
| 2811 | lru_gen_add_mm(p->mm);
|
| 2812 | task_unlock(p);
|
| 2813 | }
|
| 2814 |
|
| 2815 | wake_up_new_task(p);
|
| 2816 |
|
| 2817 |
|
| 2818 | if (unlikely(trace))
|
| 2819 | ptrace_event_pid(trace, pid);
|
| 2820 |
|
| 2821 | if (clone_flags & CLONE_VFORK) {
|
| 2822 | if (!wait_for_vfork_done(p, &vfork))
|
| 2823 | ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid);
|
| 2824 | }
|
| 2825 |
|
| 2826 | put_pid(pid);
|
| 2827 | return nr;
|
| 2828 | }
|
| 2829 |
|
| 2830 | |
| 2831 | * Create a kernel thread.
|
| 2832 |
|
| 2833 | pid_t kernel_thread(int (*fn)(void *), void *arg, const char *name,
|
| 2834 | unsigned long flags)
|
| 2835 | {
|
| 2836 | struct kernel_clone_args args = {
|
| 2837 | .flags = ((lower_32_bits(flags) | CLONE_VM |
|
| 2838 | CLONE_UNTRACED) & ~CSIGNAL),
|
| 2839 | .exit_signal = (lower_32_bits(flags) & CSIGNAL),
|
| 2840 | .fn = fn,
|
| 2841 | .fn_arg = arg,
|
| 2842 | .name = name,
|
| 2843 | .kthread = 1,
|
| 2844 | };
|
| 2845 |
|
| 2846 | return kernel_clone(&args);
|
| 2847 | }
|
| 2848 |
|
| 2849 | |
| 2850 | * Create a user mode thread.
|
| 2851 |
|
| 2852 | pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags)
|
| 2853 | {
|
| 2854 | struct kernel_clone_args args = {
|
| 2855 | .flags = ((lower_32_bits(flags) | CLONE_VM |
|
| 2856 | CLONE_UNTRACED) & ~CSIGNAL),
|
| 2857 | .exit_signal = (lower_32_bits(flags) & CSIGNAL),
|
| 2858 | .fn = fn,
|
| 2859 | .fn_arg = arg,
|
| 2860 | };
|
| 2861 |
|
| 2862 | return kernel_clone(&args);
|
| 2863 | }
|
| 2864 |
|
| 2865 | #ifdef __ARCH_WANT_SYS_FORK
|
| 2866 | SYSCALL_DEFINE0(fork)
|
| 2867 | {
|
| 2868 | #ifdef CONFIG_MMU
|
| 2869 | struct kernel_clone_args args = {
|
| 2870 | .exit_signal = SIGCHLD,
|
| 2871 | };
|
| 2872 |
|
| 2873 | return kernel_clone(&args);
|
| 2874 | #else
|
| 2875 |
|
| 2876 | return -EINVAL;
|
| 2877 | #endif
|
| 2878 | }
|
| 2879 | #endif
|
| 2880 |
|
| 2881 | #ifdef __ARCH_WANT_SYS_VFORK
|
| 2882 | SYSCALL_DEFINE0(vfork)
|
| 2883 | {
|
| 2884 | struct kernel_clone_args args = {
|
| 2885 | .flags = CLONE_VFORK | CLONE_VM,
|
| 2886 | .exit_signal = SIGCHLD,
|
| 2887 | };
|
| 2888 |
|
| 2889 | return kernel_clone(&args);
|
| 2890 | }
|
| 2891 | #endif
|
| 2892 |
|
| 2893 | #ifdef __ARCH_WANT_SYS_CLONE
|
| 2894 | #ifdef CONFIG_CLONE_BACKWARDS
|
| 2895 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
|
| 2896 | int __user *, parent_tidptr,
|
| 2897 | unsigned long, tls,
|
| 2898 | int __user *, child_tidptr)
|
| 2899 | #elif defined(CONFIG_CLONE_BACKWARDS2)
|
| 2900 | SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags,
|
| 2901 | int __user *, parent_tidptr,
|
| 2902 | int __user *, child_tidptr,
|
| 2903 | unsigned long, tls)
|
| 2904 | #elif defined(CONFIG_CLONE_BACKWARDS3)
|
| 2905 | SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp,
|
| 2906 | int, stack_size,
|
| 2907 | int __user *, parent_tidptr,
|
| 2908 | int __user *, child_tidptr,
|
| 2909 | unsigned long, tls)
|
| 2910 | #else
|
| 2911 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
|
| 2912 | int __user *, parent_tidptr,
|
| 2913 | int __user *, child_tidptr,
|
| 2914 | unsigned long, tls)
|
| 2915 | #endif
|
| 2916 | {
|
| 2917 | struct kernel_clone_args args = {
|
| 2918 | .flags = (lower_32_bits(clone_flags) & ~CSIGNAL),
|
| 2919 | .pidfd = parent_tidptr,
|
| 2920 | .child_tid = child_tidptr,
|
| 2921 | .parent_tid = parent_tidptr,
|
| 2922 | .exit_signal = (lower_32_bits(clone_flags) & CSIGNAL),
|
| 2923 | .stack = newsp,
|
| 2924 | .tls = tls,
|
| 2925 | };
|
| 2926 |
|
| 2927 | return kernel_clone(&args);
|
| 2928 | }
|
| 2929 | #endif
|
| 2930 |
|
| 2931 | noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
|
| 2932 | struct clone_args __user *uargs,
|
| 2933 | size_t usize)
|
| 2934 | {
|
| 2935 | int err;
|
| 2936 | struct clone_args args;
|
| 2937 | pid_t *kset_tid = kargs->set_tid;
|
| 2938 |
|
| 2939 | BUILD_BUG_ON(offsetofend(struct clone_args, tls) !=
|
| 2940 | CLONE_ARGS_SIZE_VER0);
|
| 2941 | BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) !=
|
| 2942 | CLONE_ARGS_SIZE_VER1);
|
| 2943 | BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) !=
|
| 2944 | CLONE_ARGS_SIZE_VER2);
|
| 2945 | BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2);
|
| 2946 |
|
| 2947 | if (unlikely(usize > PAGE_SIZE))
|
| 2948 | return -E2BIG;
|
| 2949 | if (unlikely(usize < CLONE_ARGS_SIZE_VER0))
|
| 2950 | return -EINVAL;
|
| 2951 |
|
| 2952 | err = copy_struct_from_user(&args, sizeof(args), uargs, usize);
|
| 2953 | if (err)
|
| 2954 | return err;
|
| 2955 |
|
| 2956 | if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL))
|
| 2957 | return -EINVAL;
|
| 2958 |
|
| 2959 | if (unlikely(!args.set_tid && args.set_tid_size > 0))
|
| 2960 | return -EINVAL;
|
| 2961 |
|
| 2962 | if (unlikely(args.set_tid && args.set_tid_size == 0))
|
| 2963 | return -EINVAL;
|
| 2964 |
|
| 2965 | |
| 2966 | * Verify that higher 32bits of exit_signal are unset and that
|
| 2967 | * it is a valid signal
|
| 2968 |
|
| 2969 | if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) ||
|
| 2970 | !valid_signal(args.exit_signal)))
|
| 2971 | return -EINVAL;
|
| 2972 |
|
| 2973 | if ((args.flags & CLONE_INTO_CGROUP) &&
|
| 2974 | (args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2))
|
| 2975 | return -EINVAL;
|
| 2976 |
|
| 2977 | *kargs = (struct kernel_clone_args){
|
| 2978 | .flags = args.flags,
|
| 2979 | .pidfd = u64_to_user_ptr(args.pidfd),
|
| 2980 | .child_tid = u64_to_user_ptr(args.child_tid),
|
| 2981 | .parent_tid = u64_to_user_ptr(args.parent_tid),
|
| 2982 | .exit_signal = args.exit_signal,
|
| 2983 | .stack = args.stack,
|
| 2984 | .stack_size = args.stack_size,
|
| 2985 | .tls = args.tls,
|
| 2986 | .set_tid_size = args.set_tid_size,
|
| 2987 | .cgroup = args.cgroup,
|
| 2988 | };
|
| 2989 |
|
| 2990 | if (args.set_tid &&
|
| 2991 | copy_from_user(kset_tid, u64_to_user_ptr(args.set_tid),
|
| 2992 | (kargs->set_tid_size * sizeof(pid_t))))
|
| 2993 | return -EFAULT;
|
| 2994 |
|
| 2995 | kargs->set_tid = kset_tid;
|
| 2996 |
|
| 2997 | return 0;
|
| 2998 | }
|
| 2999 |
|
| 3000 | |
| 3001 | * clone3_stack_valid - check and prepare stack
|
| 3002 | * @kargs: kernel clone args
|
| 3003 | *
|
| 3004 | * Verify that the stack arguments userspace gave us are sane.
|
| 3005 | * In addition, set the stack direction for userspace since it's easy for us to
|
| 3006 | * determine.
|
| 3007 |
|
| 3008 | static inline bool clone3_stack_valid(struct kernel_clone_args *kargs)
|
| 3009 | {
|
| 3010 | if (kargs->stack == 0) {
|
| 3011 | if (kargs->stack_size > 0)
|
| 3012 | return false;
|
| 3013 | } else {
|
| 3014 | if (kargs->stack_size == 0)
|
| 3015 | return false;
|
| 3016 |
|
| 3017 | if (!access_ok((void __user *)kargs->stack, kargs->stack_size))
|
| 3018 | return false;
|
| 3019 |
|
| 3020 | #if !defined(CONFIG_STACK_GROWSUP)
|
| 3021 | kargs->stack += kargs->stack_size;
|
| 3022 | #endif
|
| 3023 | }
|
| 3024 |
|
| 3025 | return true;
|
| 3026 | }
|
| 3027 |
|
| 3028 | static bool clone3_args_valid(struct kernel_clone_args *kargs)
|
| 3029 | {
|
| 3030 |
|
| 3031 | if (kargs->flags &
|
| 3032 | ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP))
|
| 3033 | return false;
|
| 3034 |
|
| 3035 | |
| 3036 | * - make the CLONE_DETACHED bit reusable for clone3
|
| 3037 | * - make the CSIGNAL bits reusable for clone3
|
| 3038 |
|
| 3039 | if (kargs->flags & (CLONE_DETACHED | (CSIGNAL & (~CLONE_NEWTIME))))
|
| 3040 | return false;
|
| 3041 |
|
| 3042 | if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) ==
|
| 3043 | (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND))
|
| 3044 | return false;
|
| 3045 |
|
| 3046 | if ((kargs->flags & (CLONE_THREAD | CLONE_PARENT)) &&
|
| 3047 | kargs->exit_signal)
|
| 3048 | return false;
|
| 3049 |
|
| 3050 | if (!clone3_stack_valid(kargs))
|
| 3051 | return false;
|
| 3052 |
|
| 3053 | return true;
|
| 3054 | }
|
| 3055 |
|
| 3056 | |
| 3057 | * sys_clone3 - create a new process with specific properties
|
| 3058 | * @uargs: argument structure
|
| 3059 | * @size: size of @uargs
|
| 3060 | *
|
| 3061 | * clone3() is the extensible successor to clone()/clone2().
|
| 3062 | * It takes a struct as argument that is versioned by its size.
|
| 3063 | *
|
| 3064 | * Return: On success, a positive PID for the child process.
|
| 3065 | * On error, a negative errno number.
|
| 3066 |
|
| 3067 | SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size)
|
| 3068 | {
|
| 3069 | int err;
|
| 3070 |
|
| 3071 | struct kernel_clone_args kargs;
|
| 3072 | pid_t set_tid[MAX_PID_NS_LEVEL];
|
| 3073 |
|
| 3074 | #ifdef __ARCH_BROKEN_SYS_CLONE3
|
| 3075 | #warning clone3() entry point is missing, please fix
|
| 3076 | return -ENOSYS;
|
| 3077 | #endif
|
| 3078 |
|
| 3079 | kargs.set_tid = set_tid;
|
| 3080 |
|
| 3081 | err = copy_clone_args_from_user(&kargs, uargs, size);
|
| 3082 | if (err)
|
| 3083 | return err;
|
| 3084 |
|
| 3085 | if (!clone3_args_valid(&kargs))
|
| 3086 | return -EINVAL;
|
| 3087 |
|
| 3088 | return kernel_clone(&kargs);
|
| 3089 | }
|
| 3090 |
|
| 3091 | void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data)
|
| 3092 | {
|
| 3093 | struct task_struct *leader, *parent, *child;
|
| 3094 | int res;
|
| 3095 |
|
| 3096 | read_lock(&tasklist_lock);
|
| 3097 | leader = top = top->group_leader;
|
| 3098 | down:
|
| 3099 | for_each_thread(leader, parent) {
|
| 3100 | list_for_each_entry(child, &parent->children, sibling) {
|
| 3101 | res = visitor(child, data);
|
| 3102 | if (res) {
|
| 3103 | if (res < 0)
|
| 3104 | goto out;
|
| 3105 | leader = child;
|
| 3106 | goto down;
|
| 3107 | }
|
| 3108 | up:
|
| 3109 | ;
|
| 3110 | }
|
| 3111 | }
|
| 3112 |
|
| 3113 | if (leader != top) {
|
| 3114 | child = leader;
|
| 3115 | parent = child->real_parent;
|
| 3116 | leader = parent->group_leader;
|
| 3117 | goto up;
|
| 3118 | }
|
| 3119 | out:
|
| 3120 | read_unlock(&tasklist_lock);
|
| 3121 | }
|
| 3122 |
|
| 3123 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN
|
| 3124 | #define ARCH_MIN_MMSTRUCT_ALIGN 0
|
| 3125 | #endif
|
| 3126 |
|
| 3127 | static void sighand_ctor(void *data)
|
| 3128 | {
|
| 3129 | struct sighand_struct *sighand = data;
|
| 3130 |
|
| 3131 | spin_lock_init(&sighand->siglock);
|
| 3132 | init_waitqueue_head(&sighand->signalfd_wqh);
|
| 3133 | }
|
| 3134 |
|
| 3135 | void __init mm_cache_init(void)
|
| 3136 | {
|
| 3137 | unsigned int mm_size;
|
| 3138 |
|
| 3139 | |
| 3140 | * The mm_cpumask is located at the end of mm_struct, and is
|
| 3141 | * dynamically sized based on the maximum CPU number this system
|
| 3142 | * can have, taking hotplug into account (nr_cpu_ids).
|
| 3143 |
|
| 3144 | mm_size = sizeof(struct mm_struct) + cpumask_size() + mm_cid_size();
|
| 3145 |
|
| 3146 | mm_cachep = kmem_cache_create_usercopy("mm_struct",
|
| 3147 | mm_size, ARCH_MIN_MMSTRUCT_ALIGN,
|
| 3148 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
|
| 3149 | offsetof(struct mm_struct, saved_auxv),
|
| 3150 | sizeof_field(struct mm_struct, saved_auxv),
|
| 3151 | NULL);
|
| 3152 | }
|
| 3153 |
|
| 3154 | void __init proc_caches_init(void)
|
| 3155 | {
|
| 3156 | sighand_cachep = kmem_cache_create("sighand_cache",
|
| 3157 | sizeof(struct sighand_struct), 0,
|
| 3158 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU|
|
| 3159 | SLAB_ACCOUNT, sighand_ctor);
|
| 3160 | signal_cachep = kmem_cache_create("signal_cache",
|
| 3161 | sizeof(struct signal_struct), 0,
|
| 3162 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
|
| 3163 | NULL);
|
| 3164 | files_cachep = kmem_cache_create("files_cache",
|
| 3165 | sizeof(struct files_struct), 0,
|
| 3166 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
|
| 3167 | NULL);
|
| 3168 | fs_cachep = kmem_cache_create("fs_cache",
|
| 3169 | sizeof(struct fs_struct), 0,
|
| 3170 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
|
| 3171 | NULL);
|
| 3172 |
|
| 3173 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
|
| 3174 | #ifdef CONFIG_PER_VMA_LOCK
|
| 3175 | vma_lock_cachep = KMEM_CACHE(vma_lock, SLAB_PANIC|SLAB_ACCOUNT);
|
| 3176 | #endif
|
| 3177 | mmap_init();
|
| 3178 | nsproxy_cache_init();
|
| 3179 | }
|
| 3180 |
|
| 3181 | |
| 3182 | * Check constraints on flags passed to the unshare system call.
|
| 3183 |
|
| 3184 | static int check_unshare_flags(unsigned long unshare_flags)
|
| 3185 | {
|
| 3186 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
|
| 3187 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
|
| 3188 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
|
| 3189 | CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP|
|
| 3190 | CLONE_NEWTIME))
|
| 3191 | return -EINVAL;
|
| 3192 | |
| 3193 | * Not implemented, but pretend it works if there is nothing
|
| 3194 | * to unshare. Note that unsharing the address space or the
|
| 3195 | * signal handlers also need to unshare the signal queues (aka
|
| 3196 | * CLONE_THREAD).
|
| 3197 |
|
| 3198 | if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) {
|
| 3199 | if (!thread_group_empty(current))
|
| 3200 | return -EINVAL;
|
| 3201 | }
|
| 3202 | if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
|
| 3203 | if (refcount_read(¤t->sighand->count) > 1)
|
| 3204 | return -EINVAL;
|
| 3205 | }
|
| 3206 | if (unshare_flags & CLONE_VM) {
|
| 3207 | if (!current_is_single_threaded())
|
| 3208 | return -EINVAL;
|
| 3209 | }
|
| 3210 |
|
| 3211 | return 0;
|
| 3212 | }
|
| 3213 |
|
| 3214 | |
| 3215 | * Unshare the filesystem structure if it is being shared
|
| 3216 |
|
| 3217 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
|
| 3218 | {
|
| 3219 | struct fs_struct *fs = current->fs;
|
| 3220 |
|
| 3221 | if (!(unshare_flags & CLONE_FS) || !fs)
|
| 3222 | return 0;
|
| 3223 |
|
| 3224 |
|
| 3225 | if (fs->users == 1)
|
| 3226 | return 0;
|
| 3227 |
|
| 3228 | *new_fsp = copy_fs_struct(fs);
|
| 3229 | if (!*new_fsp)
|
| 3230 | return -ENOMEM;
|
| 3231 |
|
| 3232 | return 0;
|
| 3233 | }
|
| 3234 |
|
| 3235 | |
| 3236 | * Unshare file descriptor table if it is being shared
|
| 3237 |
|
| 3238 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
|
| 3239 | {
|
| 3240 | struct files_struct *fd = current->files;
|
| 3241 |
|
| 3242 | if ((unshare_flags & CLONE_FILES) &&
|
| 3243 | (fd && atomic_read(&fd->count) > 1)) {
|
| 3244 | fd = dup_fd(fd, NULL);
|
| 3245 | if (IS_ERR(fd))
|
| 3246 | return PTR_ERR(fd);
|
| 3247 | *new_fdp = fd;
|
| 3248 | }
|
| 3249 |
|
| 3250 | return 0;
|
| 3251 | }
|
| 3252 |
|
| 3253 | |
| 3254 | * unshare allows a process to 'unshare' part of the process
|
| 3255 | * context which was originally shared using clone. copy_*
|
| 3256 | * functions used by kernel_clone() cannot be used here directly
|
| 3257 | * because they modify an inactive task_struct that is being
|
| 3258 | * constructed. Here we are modifying the current, active,
|
| 3259 | * task_struct.
|
| 3260 |
|
| 3261 | int ksys_unshare(unsigned long unshare_flags)
|
| 3262 | {
|
| 3263 | struct fs_struct *fs, *new_fs = NULL;
|
| 3264 | struct files_struct *new_fd = NULL;
|
| 3265 | struct cred *new_cred = NULL;
|
| 3266 | struct nsproxy *new_nsproxy = NULL;
|
| 3267 | int do_sysvsem = 0;
|
| 3268 | int err;
|
| 3269 |
|
| 3270 | |
| 3271 | * If unsharing a user namespace must also unshare the thread group
|
| 3272 | * and unshare the filesystem root and working directories.
|
| 3273 |
|
| 3274 | if (unshare_flags & CLONE_NEWUSER)
|
| 3275 | unshare_flags |= CLONE_THREAD | CLONE_FS;
|
| 3276 | |
| 3277 | * If unsharing vm, must also unshare signal handlers.
|
| 3278 |
|
| 3279 | if (unshare_flags & CLONE_VM)
|
| 3280 | unshare_flags |= CLONE_SIGHAND;
|
| 3281 | |
| 3282 | * If unsharing a signal handlers, must also unshare the signal queues.
|
| 3283 |
|
| 3284 | if (unshare_flags & CLONE_SIGHAND)
|
| 3285 | unshare_flags |= CLONE_THREAD;
|
| 3286 | |
| 3287 | * If unsharing namespace, must also unshare filesystem information.
|
| 3288 |
|
| 3289 | if (unshare_flags & CLONE_NEWNS)
|
| 3290 | unshare_flags |= CLONE_FS;
|
| 3291 |
|
| 3292 | err = check_unshare_flags(unshare_flags);
|
| 3293 | if (err)
|
| 3294 | goto bad_unshare_out;
|
| 3295 | |
| 3296 | * CLONE_NEWIPC must also detach from the undolist: after switching
|
| 3297 | * to a new ipc namespace, the semaphore arrays from the old
|
| 3298 | * namespace are unreachable.
|
| 3299 |
|
| 3300 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
|
| 3301 | do_sysvsem = 1;
|
| 3302 | err = unshare_fs(unshare_flags, &new_fs);
|
| 3303 | if (err)
|
| 3304 | goto bad_unshare_out;
|
| 3305 | err = unshare_fd(unshare_flags, &new_fd);
|
| 3306 | if (err)
|
| 3307 | goto bad_unshare_cleanup_fs;
|
| 3308 | err = unshare_userns(unshare_flags, &new_cred);
|
| 3309 | if (err)
|
| 3310 | goto bad_unshare_cleanup_fd;
|
| 3311 | err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
|
| 3312 | new_cred, new_fs);
|
| 3313 | if (err)
|
| 3314 | goto bad_unshare_cleanup_cred;
|
| 3315 |
|
| 3316 | if (new_cred) {
|
| 3317 | err = set_cred_ucounts(new_cred);
|
| 3318 | if (err)
|
| 3319 | goto bad_unshare_cleanup_cred;
|
| 3320 | }
|
| 3321 |
|
| 3322 | if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
|
| 3323 | if (do_sysvsem) {
|
| 3324 | |
| 3325 | * CLONE_SYSVSEM is equivalent to sys_exit().
|
| 3326 |
|
| 3327 | exit_sem(current);
|
| 3328 | }
|
| 3329 | if (unshare_flags & CLONE_NEWIPC) {
|
| 3330 |
|
| 3331 | exit_shm(current);
|
| 3332 | shm_init_task(current);
|
| 3333 | }
|
| 3334 |
|
| 3335 | if (new_nsproxy)
|
| 3336 | switch_task_namespaces(current, new_nsproxy);
|
| 3337 |
|
| 3338 | task_lock(current);
|
| 3339 |
|
| 3340 | if (new_fs) {
|
| 3341 | fs = current->fs;
|
| 3342 | spin_lock(&fs->lock);
|
| 3343 | current->fs = new_fs;
|
| 3344 | if (--fs->users)
|
| 3345 | new_fs = NULL;
|
| 3346 | else
|
| 3347 | new_fs = fs;
|
| 3348 | spin_unlock(&fs->lock);
|
| 3349 | }
|
| 3350 |
|
| 3351 | if (new_fd)
|
| 3352 | swap(current->files, new_fd);
|
| 3353 |
|
| 3354 | task_unlock(current);
|
| 3355 |
|
| 3356 | if (new_cred) {
|
| 3357 |
|
| 3358 | commit_creds(new_cred);
|
| 3359 | new_cred = NULL;
|
| 3360 | }
|
| 3361 | }
|
| 3362 |
|
| 3363 | perf_event_namespaces(current);
|
| 3364 |
|
| 3365 | bad_unshare_cleanup_cred:
|
| 3366 | if (new_cred)
|
| 3367 | put_cred(new_cred);
|
| 3368 | bad_unshare_cleanup_fd:
|
| 3369 | if (new_fd)
|
| 3370 | put_files_struct(new_fd);
|
| 3371 |
|
| 3372 | bad_unshare_cleanup_fs:
|
| 3373 | if (new_fs)
|
| 3374 | free_fs_struct(new_fs);
|
| 3375 |
|
| 3376 | bad_unshare_out:
|
| 3377 | return err;
|
| 3378 | }
|
| 3379 |
|
| 3380 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
|
| 3381 | {
|
| 3382 | return ksys_unshare(unshare_flags);
|
| 3383 | }
|
| 3384 |
|
| 3385 | |
| 3386 | * Helper to unshare the files of the current task.
|
| 3387 | * We don't want to expose copy_files internals to
|
| 3388 | * the exec layer of the kernel.
|
| 3389 |
|
| 3390 |
|
| 3391 | int unshare_files(void)
|
| 3392 | {
|
| 3393 | struct task_struct *task = current;
|
| 3394 | struct files_struct *old, *copy = NULL;
|
| 3395 | int error;
|
| 3396 |
|
| 3397 | error = unshare_fd(CLONE_FILES, ©);
|
| 3398 | if (error || !copy)
|
| 3399 | return error;
|
| 3400 |
|
| 3401 | old = task->files;
|
| 3402 | task_lock(task);
|
| 3403 | task->files = copy;
|
| 3404 | task_unlock(task);
|
| 3405 | put_files_struct(old);
|
| 3406 | return 0;
|
| 3407 | }
|
| 3408 |
|
| 3409 | int sysctl_max_threads(const struct ctl_table *table, int write,
|
| 3410 | void *buffer, size_t *lenp, loff_t *ppos)
|
| 3411 | {
|
| 3412 | struct ctl_table t;
|
| 3413 | int ret;
|
| 3414 | int threads = max_threads;
|
| 3415 | int min = 1;
|
| 3416 | int max = MAX_THREADS;
|
| 3417 |
|
| 3418 | t = *table;
|
| 3419 | t.data = &threads;
|
| 3420 | t.extra1 = &min;
|
| 3421 | t.extra2 = &max;
|
| 3422 |
|
| 3423 | ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
|
| 3424 | if (ret || !write)
|
| 3425 | return ret;
|
| 3426 |
|
| 3427 | max_threads = threads;
|
| 3428 |
|
| 3429 | return 0;
|
| 3430 | }
|