lkml.org 
[lkml]   [2013]   [Dec]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: process 'stuck' at exit.
From
Date
On Tue, 2013-12-10 at 15:49 -0500, Dave Jones wrote:
> On Tue, Dec 10, 2013 at 09:35:59PM +0100, Oleg Nesterov wrote:
> > Dave, I must have missed something, help.
> >
> > I am looking at the first message and I can't understand who stuck
> > "at exit".
> >
> > The trace shows that the task with pid=10818 called sys_futex() ?
> >
> > Perhaps "exit" means the userspace paths?
>
> pid 1131 is wait()'ing for 10818 to exit
>
> pid 1130 is periodically sending SIGKILL to 10818 because it's gotten
> tired of waiting. 10818 is ignoring these because it's stuck in a loop
> somewhere in the kernel.
>
> I tried attaching to 10818 with gdb, and it just hangs.
> (possibly because its weird stack situation [see 1st post])
>
> by inspecting the shared mapping that all processes have (by gdb'ing 1130)
> I can see that 10818 did all its full run without incident, and the
> "exit child" flag in the fuzzer had been in set.
>
> The last 'random syscall' the fuzzer did was to sys_accept4, so the futex call
> must come from somewhere in libc maybe ?

If that is the case, then Linus' requeue_pi path is highly unlikely as
FUTEX_CMP_REQUEUE_PI is not used by glibc (yet). That gives me hope as
that way there be dragons. Knowing exactly what syscall was made would
be very useful, but I don't know if that information is even available
anymore.

--
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel




\
 
 \ /
  Last update: 2013-12-10 22:21    [W:0.354 / U:0.696 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site