projects/linux·commit 3ed4c058

Merge branch 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc

3ed4c058 · Linus Torvalds <[email protected]> · 2011-05-20 13:33:21 -07:00

* 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc: (41 commits)
  signal: trivial, fix the "timespec declared inside parameter list" warning
  job control: reorganize wait_task_stopped()
  ptrace: fix signal->wait_chldexit usage in task_clear_group_stop_trapping()
  signal: sys_sigprocmask() needs retarget_shared_pending()
  signal: cleanup sys_sigprocmask()
  signal: rename signandsets() to sigandnsets()
  signal: do_sigtimedwait() needs retarget_shared_pending()
  signal: introduce do_sigtimedwait() to factor out compat/native code
  signal: sys_rt_sigtimedwait: simplify the timeout logic
  signal: cleanup sys_rt_sigprocmask()
  x86: signal: sys_rt_sigreturn() should use set_current_blocked()
  x86: signal: handle_signal() should use set_current_blocked()
  signal: sigprocmask() should do retarget_shared_pending()
  signal: sigprocmask: narrow the scope of ->siglock
  signal: retarget_shared_pending: optimize while_each_thread() loop
  signal: retarget_shared_pending: consider shared/unblocked signals only
  signal: introduce retarget_shared_pending()
  ptrace: ptrace_check_attach() should not do s/STOPPED/TRACED/
  signal: Turn SIGNAL_STOP_DEQUEUED into GROUP_STOP_DEQUEUED
  signal: do_signal_stop: Remove the unneeded task_clear_group_stop_pending()
  ...
Commit
3ed4c0583daa34dedb568b26ff99e5a7b58db612
Parents
ad947175 · bd715d9a

Merge commit. Changes below are compared with the first parent: ad947175.

Changes

9 files changed · +659 −366

FileStatusAddDelContent
arch/x86/kernel/signal.cmodified+5−9View file
fs/exec.cmodified+1−0View file
include/linux/sched.hmodified+14−3View file
include/linux/signal.hmodified+9−4View file
include/linux/tracehook.hmodified+0−27View file
kernel/compat.cmodified+7−40View file
kernel/exit.cmodified+88−22View file
kernel/ptrace.cmodified+81−37View file
kernel/signal.cmodified+454−224View file

Only the first 600 diff lines are shown. Download the complete patch.

arch/x86/kernel/signal.c

View file
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 4fd173c..40a2493 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -601,10 +601,7 @@ long sys_rt_sigreturn(struct pt_regs *regs)
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
- spin_lock_irq(&current->sighand->siglock);
- current->blocked = set;
- recalc_sigpending();
- spin_unlock_irq(&current->sighand->siglock);
+ set_current_blocked(&set);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
goto badframe;
@@ -682,6 +679,7 @@ static int
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
sigset_t *oldset, struct pt_regs *regs)
{
+ sigset_t blocked;
int ret;
/* Are we from a system call? */
@@ -741,12 +739,10 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
*/
regs->flags &= ~X86_EFLAGS_TF;
- spin_lock_irq(&current->sighand->siglock);
- sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
+ sigorsets(&blocked, &current->blocked, &ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
- sigaddset(&current->blocked, sig);
- recalc_sigpending();
- spin_unlock_irq(&current->sighand->siglock);
+ sigaddset(&blocked, sig);
+ set_current_blocked(&blocked);
tracehook_signal_handler(sig, info, ka, regs,
test_thread_flag(TIF_SINGLESTEP));

fs/exec.c

View file
diff --git a/fs/exec.c b/fs/exec.c
index 5e62d26..8328beb 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1659,6 +1659,7 @@ static int zap_process(struct task_struct *start, int exit_code)
t = start;
do {
+ task_clear_group_stop_pending(t);
if (t != current && t->mm) {
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);

include/linux/sched.h

View file
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 12211e1..885c4f2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -653,9 +653,8 @@ struct signal_struct {
* Bits in flags field of signal_struct.
*/
#define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */
-#define SIGNAL_STOP_DEQUEUED 0x00000002 /* stop signal dequeued */
-#define SIGNAL_STOP_CONTINUED 0x00000004 /* SIGCONT since WCONTINUED reap */
-#define SIGNAL_GROUP_EXIT 0x00000008 /* group exit in progress */
+#define SIGNAL_STOP_CONTINUED 0x00000002 /* SIGCONT since WCONTINUED reap */
+#define SIGNAL_GROUP_EXIT 0x00000004 /* group exit in progress */
/*
* Pending notifications to parent.
*/
@@ -1251,6 +1250,7 @@ struct task_struct {
int exit_state;
int exit_code, exit_signal;
int pdeath_signal; /* The signal sent when the parent dies */
+ unsigned int group_stop; /* GROUP_STOP_*, siglock protected */
/* ??? */
unsigned int personality;
unsigned did_exec:1;
@@ -1771,6 +1771,17 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
#define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
#define used_math() tsk_used_math(current)
+/*
+ * task->group_stop flags
+ */
+#define GROUP_STOP_SIGMASK 0xffff /* signr of the last group stop */
+#define GROUP_STOP_PENDING (1 << 16) /* task should stop for group stop */
+#define GROUP_STOP_CONSUME (1 << 17) /* consume group stop count */
+#define GROUP_STOP_TRAPPING (1 << 18) /* switching from STOPPED to TRACED */
+#define GROUP_STOP_DEQUEUED (1 << 19) /* stop signal dequeued */
+
+extern void task_clear_group_stop_pending(struct task_struct *task);
+
#ifdef CONFIG_PREEMPT_RCU
#define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */

include/linux/signal.h

View file
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 29a68ac..a822300 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -125,13 +125,13 @@ _SIG_SET_BINOP(sigorsets, _sig_or)
#define _sig_and(x,y) ((x) & (y))
_SIG_SET_BINOP(sigandsets, _sig_and)
-#define _sig_nand(x,y) ((x) & ~(y))
-_SIG_SET_BINOP(signandsets, _sig_nand)
+#define _sig_andn(x,y) ((x) & ~(y))
+_SIG_SET_BINOP(sigandnsets, _sig_andn)
#undef _SIG_SET_BINOP
#undef _sig_or
#undef _sig_and
-#undef _sig_nand
+#undef _sig_andn
#define _SIG_SET_OP(name, op) \
static inline void name(sigset_t *set) \
@@ -236,6 +236,9 @@ static inline int valid_signal(unsigned long sig)
return sig <= _NSIG ? 1 : 0;
}
+struct timespec;
+struct pt_regs;
+
extern int next_signal(struct sigpending *pending, sigset_t *mask);
extern int do_send_sig_info(int sig, struct siginfo *info,
struct task_struct *p, bool group);
@@ -244,10 +247,12 @@ extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
extern long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig,
siginfo_t *info);
extern long do_sigpending(void __user *, unsigned long);
+extern int do_sigtimedwait(const sigset_t *, siginfo_t *,
+ const struct timespec *);
extern int sigprocmask(int, sigset_t *, sigset_t *);
+extern void set_current_blocked(const sigset_t *);
extern int show_unhandled_signals;
-struct pt_regs;
extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, struct pt_regs *regs, void *cookie);
extern void exit_signals(struct task_struct *tsk);

include/linux/tracehook.h

View file
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index ebcfa4e..e95f523 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -469,33 +469,6 @@ static inline int tracehook_get_signal(struct task_struct *task,
}
/**
- * tracehook_notify_jctl - report about job control stop/continue
- * @notify: zero, %CLD_STOPPED or %CLD_CONTINUED
- * @why: %CLD_STOPPED or %CLD_CONTINUED
- *
- * This is called when we might call do_notify_parent_cldstop().
- *
- * @notify is zero if we would not ordinarily send a %SIGCHLD,
- * or is the %CLD_STOPPED or %CLD_CONTINUED .si_code for %SIGCHLD.
- *
- * @why is %CLD_STOPPED when about to stop for job control;
- * we are already in %TASK_STOPPED state, about to call schedule().
- * It might also be that we have just exited (check %PF_EXITING),
- * but need to report that a group-wide stop is complete.
- *
- * @why is %CLD_CONTINUED when waking up after job control stop and
- * ready to make a delayed @notify report.
- *
- * Return the %CLD_* value for %SIGCHLD, or zero to generate no signal.
- *
- * Called with the siglock held.
- */
-static inline int tracehook_notify_jctl(int notify, int why)
-{
- return notify ?: (current->ptrace & PT_PTRACED) ? why : 0;
-}
-
-/**
* tracehook_finish_jctl - report about return from job control stop
*
* This is called by do_signal_stop() after wakeup.

kernel/compat.c

View file
diff --git a/kernel/compat.c b/kernel/compat.c
index 38b1d2c..9214dcd 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -890,10 +890,9 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
{
compat_sigset_t s32;
sigset_t s;
- int sig;
struct timespec t;
siginfo_t info;
- long ret, timeout = 0;
+ long ret;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
@@ -901,51 +900,19 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
if (copy_from_user(&s32, uthese, sizeof(compat_sigset_t)))
return -EFAULT;
sigset_from_compat(&s, &s32);
- sigdelsetmask(&s,sigmask(SIGKILL)|sigmask(SIGSTOP));
- signotset(&s);
if (uts) {
- if (get_compat_timespec (&t, uts))
+ if (get_compat_timespec(&t, uts))
return -EFAULT;
- if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0
- || t.tv_sec < 0)
- return -EINVAL;
}
- spin_lock_irq(&current->sighand->siglock);
- sig = dequeue_signal(current, &s, &info);
- if (!sig) {
- timeout = MAX_SCHEDULE_TIMEOUT;
- if (uts)
- timeout = timespec_to_jiffies(&t)
- +(t.tv_sec || t.tv_nsec);
- if (timeout) {
- current->real_blocked = current->blocked;
- sigandsets(&current->blocked, &current->blocked, &s);
-
- recalc_sigpending();
- spin_unlock_irq(&current->sighand->siglock);
-
- timeout = schedule_timeout_interruptible(timeout);
-
- spin_lock_irq(&current->sighand->siglock);
- sig = dequeue_signal(current, &s, &info);
- current->blocked = current->real_blocked;
- siginitset(&current->real_blocked, 0);
- recalc_sigpending();
- }
- }
- spin_unlock_irq(&current->sighand->siglock);
+ ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
- if (sig) {
- ret = sig;
- if (uinfo) {
- if (copy_siginfo_to_user32(uinfo, &info))
- ret = -EFAULT;
- }
- }else {
- ret = timeout?-EINTR:-EAGAIN;
+ if (ret > 0 && uinfo) {
+ if (copy_siginfo_to_user32(uinfo, &info))
+ ret = -EFAULT;
}
+
return ret;
}

kernel/exit.c

View file
diff --git a/kernel/exit.c b/kernel/exit.c
index 8dd8741..20a4064 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1377,11 +1377,23 @@ static int *task_stopped_code(struct task_struct *p, bool ptrace)
return NULL;
}
-/*
- * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
- * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
- * the lock and this task is uninteresting. If we return nonzero, we have
- * released the lock and the system call should return.
+/**
+ * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
+ * @wo: wait options
+ * @ptrace: is the wait for ptrace
+ * @p: task to wait for
+ *
+ * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
+ *
+ * CONTEXT:
+ * read_lock(&tasklist_lock), which is released if return value is
+ * non-zero. Also, grabs and releases @p->sighand->siglock.
+ *
+ * RETURNS:
+ * 0 if wait condition didn't exist and search for other wait conditions
+ * should continue. Non-zero return, -errno on failure and @p's pid on
+ * success, implies that tasklist_lock is released and wait condition
+ * search should terminate.
*/
static int wait_task_stopped(struct wait_opts *wo,
int ptrace, struct task_struct *p)
@@ -1397,6 +1409,9 @@ static int wait_task_stopped(struct wait_opts *wo,
if (!ptrace && !(wo->wo_flags & WUNTRACED))
return 0;
+ if (!task_stopped_code(p, ptrace))
+ return 0;
+
exit_code = 0;
spin_lock_irq(&p->sighand->siglock);
@@ -1538,33 +1553,84 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
return 0;
}
- if (likely(!ptrace) && unlikely(task_ptrace(p))) {
+ /* dead body doesn't have much to contribute */
+ if (p->exit_state == EXIT_DEAD)
+ return 0;
+
+ /* slay zombie? */
+ if (p->exit_state == EXIT_ZOMBIE) {
+ /*
+ * A zombie ptracee is only visible to its ptracer.
+ * Notification and reaping will be cascaded to the real
+ * parent when the ptracer detaches.
+ */
+ if (likely(!ptrace) && unlikely(task_ptrace(p))) {
+ /* it will become visible, clear notask_error */
+ wo->notask_error = 0;
+ return 0;
+ }
+
+ /* we don't reap group leaders with subthreads */
+ if (!delay_group_leader(p))
+ return wait_task_zombie(wo, p);
+
/*
- * This child is hidden by ptrace.
- * We aren't allowed to see it now, but eventually we will.
+ * Allow access to stopped/continued state via zombie by
+ * falling through. Clearing of notask_error is complex.
+ *
+ * When !@ptrace:
+ *
+ * If WEXITED is set, notask_error should naturally be
+ * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
+ * so, if there are live subthreads, there are events to
+ * wait for. If all subthreads are dead, it's still safe
+ * to clear - this function will be called again in finite
+ * amount time once all the subthreads are released and
+ * will then return without clearing.
+ *
+ * When @ptrace:
+ *
+ * Stopped state is per-task and thus can't change once the
+ * target task dies. Only continued and exited can happen.
+ * Clear notask_error if WCONTINUED | WEXITED.
+ */
+ if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
+ wo->notask_error = 0;
+ } else {
+ /*
+ * If @p is ptraced by a task in its real parent's group,
+ * hide group stop/continued state when looking at @p as
+ * the real parent; otherwise, a single stop can be
+ * reported twice as group and ptrace stops.
+ *
+ * If a ptracer wants to distinguish the two events for its
+ * own children, it should create a separate process which
+ * takes the role of real parent.
+ */
+ if (likely(!ptrace) && task_ptrace(p) &&
+ same_thread_group(p->parent, p->real_parent))
+ return 0;
+
+ /*
+ * @p is alive and it's gonna stop, continue or exit, so
+ * there always is something to wait for.
*/
wo->notask_error = 0;
- return 0;
}
- if (p->exit_state == EXIT_DEAD)
- return 0;
-
/*
- * We don't reap group leaders with subthreads.
+ * Wait for stopped. Depending on @ptrace, different stopped state
+ * is used and the two don't interact with each other.
*/
- if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p))
- return wait_task_zombie(wo, p);
+ ret = wait_task_stopped(wo, ptrace, p);
+ if (ret)
+ return ret;
/*
- * It's stopped or running now, so it might
- * later continue, exit, or stop again.
+ * Wait for continued. There's only one continued state and the
+ * ptracer can consume it which can confuse the real parent. Don't
+ * use WCONTINUED from ptracer. You don't need or want it.
*/
- wo->notask_error = 0;
-
- if (task_stopped_code(p, ptrace))
- return wait_task_stopped(wo, ptrace, p);
-
return wait_task_continued(wo, p);
}

kernel/ptrace.c

View file
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index dc7ab65..7a81fc0 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -38,35 +38,33 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
child->parent = new_parent;
}
-/*
- * Turn a tracing stop into a normal stop now, since with no tracer there
- * would be no way to wake it up with SIGCONT or SIGKILL. If there was a
- * signal sent that would resume the child, but didn't because it was in
- * TASK_TRACED, resume it now.
- * Requires that irqs be disabled.
- */
-static void ptrace_untrace(struct task_struct *child)
-{
- spin_lock(&child->sighand->siglock);
- if (task_is_traced(child)) {
- /*
- * If the group stop is completed or in progress,
- * this thread was already counted as stopped.
- */
- if (child->signal->flags & SIGNAL_STOP_STOPPED ||
- child->signal->group_stop_count)
- __set_task_state(child, TASK_STOPPED);
- else
- signal_wake_up(child, 1);
- }
- spin_unlock(&child->sighand->siglock);
-}
-
-/*
- * unptrace a task: move it back to its original parent and
- * remove it from the ptrace list.
+/**
+ * __ptrace_unlink - unlink ptracee and restore its execution state
+ * @child: ptracee to be unlinked
*
- * Must be called with the tasklist lock write-held.
+ * Remove @child from the ptrace list, move it back to the original parent,
+ * and restore the execution state so that it conforms to the group stop
+ * state.
+ *
+ * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
+ * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
+ * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
+ * If the ptracer is exiting, the ptracee can be in any state.
+ *
+ * After detach, the ptracee should be in a state which conforms to the
+ * group stop. If the group is stopped or in the process of stopping, the
+ * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
+ * up from TASK_TRACED.
+ *
+ * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
+ * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
+ * to but in the opposite direction of what happens while attaching to a
+ * stopped task. However, in this direction, the intermediate RUNNING
+ * state is not hidden even from the current ptracer and if it immediately
+ * re-attaches and performs a WNOHANG wait(2), it may fail.
+ *
+ * CONTEXT:
+ * write_lock_irq(tasklist_lock)
*/
void __ptrace_unlink(struct task_struct *child)
{
@@ -76,8 +74,27 @@ void __ptrace_unlink(struct task_struct *child)
child->parent = child->real_parent;
list_del_init(&child->ptrace_entry);
- if (task_is_traced(child))
- ptrace_untrace(child);
+ spin_lock(&child->sighand->siglock);
+
+ /*
+ * Reinstate GROUP_STOP_PENDING if group stop is in effect and
+ * @child isn't dead.
+ */
+ if (!(child->flags & PF_EXITING) &&
+ (child->signal->flags & SIGNAL_STOP_STOPPED ||
+ child->signal->group_stop_count))
+ child->group_stop |= GROUP_STOP_PENDING;
+
+ /*
+ * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
+ * @child in the butt. Note that @resume should be used iff @child
+ * is in TASK_TRACED; otherwise, we might unduly disrupt
+ * TASK_KILLABLE sleeps.
+ */
+ if (child->group_stop & GROUP_STOP_PENDING || task_is_traced(child))
+ signal_wake_up(child, task_is_traced(child));
+
+ spin_unlock(&child->sighand->siglock);
}
/*
@@ -96,16 +113,14 @@ int ptrace_check_attach(struct task_struct *child, int kill)
*/
read_lock(&tasklist_lock);
if ((child->ptrace & PT_PTRACED) && child->parent == current) {
- ret = 0;
/*
* child->sighand can't be NULL, release_task()
* does ptrace_unlink() before __exit_signal().
*/
spin_lock_irq(&child->sighand->siglock);
- if (task_is_stopped(child))
- child->state = TASK_TRACED;
- else if (!task_is_traced(child) && !kill)
- ret = -ESRCH;
+ WARN_ON_ONCE(task_is_stopped(child));
+ if (task_is_traced(child) || kill)
+ ret = 0;
spin_unlock_irq(&child->sighand->siglock);
}
read_unlock(&tasklist_lock);
@@ -169,6 +184,7 @@ bool ptrace_may_access(struct task_struct *task, unsigned int mode)
static int ptrace_attach(struct task_struct *task)
{
+ bool wait_trap = false;
int retval;
audit_ptrace(task);
@@ -208,12 +224,42 @@ static int ptrace_attach(struct task_struct *task)
__ptrace_link(task, current);
send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
+ spin_lock(&task->sighand->siglock);
+
+ /*
+ * If the task is already STOPPED, set GROUP_STOP_PENDING and
+ * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
+ * will be cleared if the child completes the transition or any
+ * event which clears the group stop states happens. We'll wait
+ * for the transition to complete before returning from this
+ * function.
+ *
+ * This hides STOPPED -> RUNNING -> TRACED transition from the
+ * attaching thread but a different thread in the same group can
+ * still observe the transient RUNNING state. IOW, if another
+ * thread's WNOHANG wait(2) on the stopped tracee races against
+ * ATTACH, the wait(2) may fail due to the transient RUNNING.
+ *
+ * The following task_is_stopped() test is safe as both transitions
+ * in and out of STOPPED are protected by siglock.
+ */
+ if (task_is_stopped(task)) {
+ task->group_stop |= GROUP_STOP_PENDING | GROUP_STOP_TRAPPING;
+ signal_wake_up(task, 1);
+ wait_trap = true;
+ }
+
+ spin_unlock(&task->sighand->siglock);
+
retval = 0;
unlock_tasklist:
write_unlock_irq(&tasklist_lock);
unlock_creds:
mutex_unlock(&task->signal->cred_guard_mutex);
out:
+ if (wait_trap)
+ wait_event(current->signal->wait_chldexit,
+ !(task->group_stop & GROUP_STOP_TRAPPING));
return retval;
}
@@ -316,8 +362,6 @@ static int ptrace_detach(struct task_struct *child, unsigned int data)
if (child->ptrace) {
child->exit_code = data;
dead = __ptrace_detach(current, child);
- if (!child->exit_state)
- wake_up_state(child, TASK_TRACED | TASK_STOPPED);
}
write_unlock_irq(&tasklist_lock);

kernel/signal.c

View file
diff --git a/kernel/signal.c b/kernel/signal.c
index 7165af5..ad5e818 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -124,7 +124,7 @@ static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
static int recalc_sigpending_tsk(struct task_struct *t)
{
- if (t->signal->group_stop_count > 0 ||
+ if ((t->group_stop & GROUP_STOP_PENDING) ||
PENDING(&t->pending, &t->blocked) ||
PENDING(&t->signal->shared_pending, &t->blocked)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
@@ -223,6 +223,83 @@ static inline void print_dropped_signal(int sig)
current->comm, current->pid, sig);
}
+/**
+ * task_clear_group_stop_trapping - clear group stop trapping bit
+ * @task: target task
+ *
+ * If GROUP_STOP_TRAPPING is set, a ptracer is waiting for us. Clear it
+ * and wake up the ptracer. Note that we don't need any further locking.
+ * @task->siglock guarantees that @task->parent points to the ptracer.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */

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