lkml.org 
[lkml]   [2012]   [Jan]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: Possible bug introduced in commit 9b84cca
On 12/29, Oleg Nesterov wrote:
>
> On 12/29, Oleg Nesterov wrote:
> >
> > On 12/28, Denys Vlasenko wrote:
> > >
> > > 931 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xf763dbd8) = 1048
> > > 1048 exit_group(42) = ?
> > > 931 waitpid(1048, <unfinished ...>
> > > 1048 +++ exited with 42 +++
> > > 931 <... waitpid resumed> 0xf763d3a0, 0) = -1 ECHILD (No child processes)
> >
> I've made the simple test-case, it triggers the bug.

I am going to send the hack^Wpatch below to Linus as a temporary
workaround for 3.2.

Any chance you can test it?

I did the testing too with my test-case, but it would be nice to
know if it works for you.

Thanks,

Oleg.

--- x/kernel/exit.c~ 2011-11-22 18:46:22.000000000 +0100
+++ x/kernel/exit.c 2012-01-03 14:37:17.000000000 +0100
@@ -1540,8 +1540,11 @@ static int wait_consider_task(struct wai
}

/* dead body doesn't have much to contribute */
- if (p->exit_state == EXIT_DEAD)
+ if (unlikely(p->exit_state == EXIT_DEAD)) {
+ if (likely(!ptrace) && unlikely(ptrace_reparented(p)))
+ wo->notask_error = 0;
return 0;
+ }

/* slay zombie? */
if (p->exit_state == EXIT_ZOMBIE) {


\
 
 \ /
  Last update: 2012-01-03 15:37    [from the cache]
©2003-2011 Jasper Spaans