Re: [patch] add /proc/pid/stack to dump task's stack trace

[Marcin Slusarz <marcin.slusarz@gmail.com>]

On Fri, Nov 07, 2008 at 10:03:04AM +0100, Ingo Molnar wrote:
> 
> btw., the feature works beautifully:
> 
> task sleeping/blocked:
> 
>  # cat /proc/1/stack
>  [<ffffffff802bfe75>] do_select+0x51a/0x582
>  [<ffffffff802c0059>] core_sys_select+0x17c/0x218
>  [<ffffffff802c0344>] sys_select+0x99/0xc1
>  [<ffffffff8020c23b>] system_call_fastpath+0x16/0x1b
>  [<ffffffffffffffff>] 0xffffffffffffffff
> 
> task running on this CPU:
> 
>  # cat /proc/self/stack
>  [<ffffffff80216f79>] save_stack_trace_tsk+0x26/0x44
>  [<ffffffff802f59a5>] proc_pid_stack+0x6e/0xd3
>  [<ffffffff802f6da3>] proc_info_read+0x68/0xba
>  [<ffffffff802b2f17>] vfs_read+0xa9/0xe3
>  [<ffffffff802b301f>] sys_read+0x4c/0x73
>  [<ffffffff8020c23b>] system_call_fastpath+0x16/0x1b
>  [<ffffffffffffffff>] 0xffffffffffffffff
> 
> task running on another CPU in user-space:
> 
>  # cat /proc/18579/stack
>  [<ffffffffffffffff>] 0xffffffffffffffff

so this file provides view of _kernel_ stack only?
shouldn't it be named kernel-stack then?

> task running on another CPU in kernel-space:
> 
>  # cat /proc/18579/stack
>  [<ffffffff8026f111>] audit_syscall_exit+0x9c/0xed
>  [<ffffffff80214b49>] syscall_trace_leave+0x94/0xbb
>  [<ffffffffffffffff>] 0xffffffffffffffff
> 
> 	Ingo
> --