| 1 | |
| 2 | |
| 3 | * Stack trace management functions
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| 4 | *
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| 5 | * Copyright (C) 2006 Atsushi Nemoto <[email protected]>
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| 6 |
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| 7 | #include <linux/sched.h>
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| 8 | #include <linux/sched/debug.h>
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| 9 | #include <linux/sched/task_stack.h>
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| 10 | #include <linux/stacktrace.h>
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| 11 | #include <linux/export.h>
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| 12 | #include <asm/stacktrace.h>
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| 13 |
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| 14 | |
| 15 | * Save stack-backtrace addresses into a stack_trace buffer:
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| 16 |
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| 17 | static void save_raw_context_stack(struct stack_trace *trace,
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| 18 | unsigned long reg29, int savesched)
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| 19 | {
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| 20 | unsigned long *sp = (unsigned long *)reg29;
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| 21 | unsigned long addr;
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| 22 |
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| 23 | while (!kstack_end(sp)) {
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| 24 | addr = *sp++;
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| 25 | if (__kernel_text_address(addr) &&
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| 26 | (savesched || !in_sched_functions(addr))) {
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| 27 | if (trace->skip > 0)
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| 28 | trace->skip--;
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| 29 | else
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| 30 | trace->entries[trace->nr_entries++] = addr;
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| 31 | if (trace->nr_entries >= trace->max_entries)
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| 32 | break;
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| 33 | }
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| 34 | }
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| 35 | }
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| 36 |
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| 37 | static void save_context_stack(struct stack_trace *trace,
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| 38 | struct task_struct *tsk, struct pt_regs *regs, int savesched)
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| 39 | {
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| 40 | unsigned long sp = regs->regs[29];
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| 41 | #ifdef CONFIG_KALLSYMS
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| 42 | unsigned long ra = regs->regs[31];
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| 43 | unsigned long pc = regs->cp0_epc;
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| 44 |
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| 45 | if (raw_show_trace || !__kernel_text_address(pc)) {
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| 46 | unsigned long stack_page =
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| 47 | (unsigned long)task_stack_page(tsk);
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| 48 | if (stack_page && sp >= stack_page &&
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| 49 | sp <= stack_page + THREAD_SIZE - 32)
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| 50 | save_raw_context_stack(trace, sp, savesched);
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| 51 | return;
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| 52 | }
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| 53 | do {
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| 54 | if (savesched || !in_sched_functions(pc)) {
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| 55 | if (trace->skip > 0)
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| 56 | trace->skip--;
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| 57 | else
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| 58 | trace->entries[trace->nr_entries++] = pc;
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| 59 | if (trace->nr_entries >= trace->max_entries)
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| 60 | break;
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| 61 | }
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| 62 | pc = unwind_stack(tsk, &sp, pc, &ra);
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| 63 | } while (pc);
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| 64 | #else
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| 65 | save_raw_context_stack(trace, sp, savesched);
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| 66 | #endif
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| 67 | }
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| 68 |
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| 69 | |
| 70 | * Save stack-backtrace addresses into a stack_trace buffer.
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| 71 |
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| 72 | void save_stack_trace(struct stack_trace *trace)
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| 73 | {
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| 74 | save_stack_trace_tsk(current, trace);
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| 75 | }
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| 76 | EXPORT_SYMBOL_GPL(save_stack_trace);
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| 77 |
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| 78 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
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| 79 | {
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| 80 | struct pt_regs dummyregs;
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| 81 | struct pt_regs *regs = &dummyregs;
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| 82 |
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| 83 | WARN_ON(trace->nr_entries || !trace->max_entries);
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| 84 |
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| 85 | if (tsk != current) {
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| 86 | regs->regs[29] = tsk->thread.reg29;
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| 87 | regs->regs[31] = 0;
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| 88 | regs->cp0_epc = tsk->thread.reg31;
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| 89 | } else
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| 90 | prepare_frametrace(regs);
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| 91 | save_context_stack(trace, tsk, regs, tsk == current);
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| 92 | }
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| 93 | EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
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