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ftrace/sysprof: don't trace the user stack if we are a kernel thread. 

Check that current->mm is non-NULL before attempting to trace the user
stack.

Also take depth of the kernel stack into account when comparing
against sample_max_depth.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Soeren Sandmann 2008-05-12 05:28:50 +02:00 committed by Thomas Gleixner
parent 8a9e94c1fb
commit cf3271a73b
1 changed files with 29 additions and 21 deletions
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50
kernel/trace/trace_sysprof.c
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@ -95,13 +95,12 @@ const static struct stacktrace_ops backtrace_ops = {
.address = backtrace_address,
};
static struct pt_regs *
static int
trace_kernel(struct pt_regs *regs, struct trace_array *tr,
struct trace_array_cpu *data)
{
struct backtrace_info info;
unsigned long bp;
char *user_stack;
char *stack;
info.tr = tr;
@ -119,10 +118,7 @@ trace_kernel(struct pt_regs *regs, struct trace_array *tr,
dump_trace(NULL, regs, (void *)stack, bp, &backtrace_ops, &info);
/* Now trace the user stack */
user_stack = ((char *)current->thread.sp0 - sizeof(struct pt_regs));
return (struct pt_regs *)user_stack;
return info.pos;
}
static void timer_notify(struct pt_regs *regs, int cpu)
@ -150,32 +146,44 @@ static void timer_notify(struct pt_regs *regs, int cpu)
__trace_special(tr, data, 0, 0, current->pid);
if (!is_user)
regs = trace_kernel(regs, tr, data);
i = trace_kernel(regs, tr, data);
else
i = 0;
fp = (void __user *)regs->bp;
/*
* Trace user stack if we are not a kernel thread
*/
if (current->mm && i < sample_max_depth) {
regs = (struct pt_regs *)current->thread.sp0 - 1;
__trace_special(tr, data, 2, regs->ip, 0);
fp = (void __user *)regs->bp;
for (i = 0; i < sample_max_depth; i++) {
frame.next_fp = 0;
frame.return_address = 0;
if (!copy_stack_frame(fp, &frame))
break;
if ((unsigned long)fp < regs->sp)
break;
__trace_special(tr, data, 2, regs->ip, 0);
while (i < sample_max_depth) {
frame.next_fp = 0;
frame.return_address = 0;
if (!copy_stack_frame(fp, &frame))
break;
if ((unsigned long)fp < regs->sp)
break;
__trace_special(tr, data, 2, frame.return_address,
(unsigned long)fp);
fp = frame.next_fp;
i++;
}
__trace_special(tr, data, 2, frame.return_address,
(unsigned long)fp);
fp = frame.next_fp;
}
__trace_special(tr, data, 3, current->pid, i);
/*
* Special trace entry if we overflow the max depth:
*/
if (i == sample_max_depth)
__trace_special(tr, data, -1, -1, -1);
__trace_special(tr, data, 3, current->pid, i);
}
static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)