f76e915473
Available for !SMP only at the moment. From Russell: |Basically, if a thread is running on a CPU, thread_saved_fp() is invalid. |So, the question is: what guarantees do we have here that 'tsk' is not |running on another CPU? Signed-off-by: Nicolas Pitre <nico@marvell.com> Tested-by: Lennert Buytenhek <buytenh@marvell.com> Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
95 lines
2 KiB
C
95 lines
2 KiB
C
#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/stacktrace.h>
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#include "stacktrace.h"
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int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,
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int (*fn)(struct stackframe *, void *), void *data)
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{
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struct stackframe *frame;
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do {
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/*
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* Check current frame pointer is within bounds
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*/
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if (fp < (low + 12) || fp + 4 >= high)
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break;
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frame = (struct stackframe *)(fp - 12);
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if (fn(frame, data))
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break;
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/*
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* Update the low bound - the next frame must always
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* be at a higher address than the current frame.
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*/
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low = fp + 4;
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fp = frame->fp;
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} while (fp);
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return 0;
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}
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EXPORT_SYMBOL(walk_stackframe);
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#ifdef CONFIG_STACKTRACE
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struct stack_trace_data {
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struct stack_trace *trace;
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unsigned int no_sched_functions;
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unsigned int skip;
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};
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static int save_trace(struct stackframe *frame, void *d)
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{
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struct stack_trace_data *data = d;
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struct stack_trace *trace = data->trace;
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unsigned long addr = frame->lr;
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if (data->no_sched_functions && in_sched_functions(addr))
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return 0;
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if (data->skip) {
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data->skip--;
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return 0;
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}
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trace->entries[trace->nr_entries++] = addr;
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return trace->nr_entries >= trace->max_entries;
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}
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void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
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{
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struct stack_trace_data data;
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unsigned long fp, base;
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data.trace = trace;
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data.skip = trace->skip;
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base = (unsigned long)task_stack_page(tsk);
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if (tsk != current) {
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#ifdef CONFIG_SMP
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/*
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* What guarantees do we have here that 'tsk'
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* is not running on another CPU?
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*/
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BUG();
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#else
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data.no_sched_functions = 1;
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fp = thread_saved_fp(tsk);
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#endif
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} else {
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data.no_sched_functions = 0;
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asm("mov %0, fp" : "=r" (fp));
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}
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walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
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if (trace->nr_entries < trace->max_entries)
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trace->entries[trace->nr_entries++] = ULONG_MAX;
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}
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void save_stack_trace(struct stack_trace *trace)
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{
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save_stack_trace_tsk(current, trace);
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}
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#endif
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