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proc: add /proc/*/stack

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/proc/*/stack adds the ability to query a task's stack trace. It is more
useful than /proc/*/wchan as it provides full stack trace instead of single
depth. Example output:

	$ cat /proc/self/stack
	[<c010a271>] save_stack_trace_tsk+0x17/0x35
	[<c01827b4>] proc_pid_stack+0x4a/0x76
	[<c018312d>] proc_single_show+0x4a/0x5e
	[<c016bdec>] seq_read+0xf3/0x29f
	[<c015a004>] vfs_read+0x6d/0x91
	[<c015a0c1>] sys_read+0x3b/0x60
	[<c0102eda>] syscall_call+0x7/0xb
	[<ffffffff>] 0xffffffff

[add save_stack_trace_tsk() on mips, ACK Ralf --adobriyan]
Signed-off-by: Ken Chen <kenchen@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
This commit is contained in:
Ken Chen
2008-11-10 11:26:08 +03:00
committed by Alexey Dobriyan
parent 631f9c1868
commit 2ec220e27f
3 changed files with 57 additions and 6 deletions
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38
fs/proc/base.c
View File

@@ -65,6 +65,7 @@
#include <linux/mm.h>
#include <linux/rcupdate.h>
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>
#include <linux/resource.h>
#include <linux/module.h>
#include <linux/mount.h>
@@ -337,6 +338,37 @@ static int proc_pid_wchan(struct task_struct *task, char *buffer)
}
#endif /* CONFIG_KALLSYMS */
#ifdef CONFIG_STACKTRACE
#define MAX_STACK_TRACE_DEPTH 64
static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
struct stack_trace trace;
unsigned long *entries;
int i;
entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
if (!entries)
return -ENOMEM;
trace.nr_entries = 0;
trace.max_entries = MAX_STACK_TRACE_DEPTH;
trace.entries = entries;
trace.skip = 0;
save_stack_trace_tsk(task, &trace);
for (i = 0; i < trace.nr_entries; i++) {
seq_printf(m, "[<%p>] %pS\n",
(void *)entries[i], (void *)entries[i]);
}
kfree(entries);
return 0;
}
#endif
#ifdef CONFIG_SCHEDSTATS
/*
* Provides /proc/PID/schedstat
@@ -2500,6 +2532,9 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_KALLSYMS
INF("wchan", S_IRUGO, proc_pid_wchan),
#endif
#ifdef CONFIG_STACKTRACE
ONE("stack", S_IRUSR, proc_pid_stack),
#endif
#ifdef CONFIG_SCHEDSTATS
INF("schedstat", S_IRUGO, proc_pid_schedstat),
#endif
@@ -2835,6 +2870,9 @@ static const struct pid_entry tid_base_stuff[] = {
#ifdef CONFIG_KALLSYMS
INF("wchan", S_IRUGO, proc_pid_wchan),
#endif
#ifdef CONFIG_STACKTRACE
ONE("stack", S_IRUSR, proc_pid_stack),
#endif
#ifdef CONFIG_SCHEDSTATS
INF("schedstat", S_IRUGO, proc_pid_schedstat),
#endif