Re: Asterisk deadlocks since Kernel 4.1

From: Thomas Gleixner
Date: Tue Nov 17 2015 - 14:15:53 EST


On Tue, 17 Nov 2015, Stefan Priebe - Profihost AG wrote:
> since Upgrading our Asterisk System from Kernel 3.18.17 to 4.1.13 it
> deadlocks every few hours (kill -9 is the only thing working). Booting
> with 3.18 again let it run smooth again.
>
> An strace shows asterisk is looping like this:
>
> [pid 6068] timerfd_gettime(8, , {it_interval={0, 20000000},
> it_value={0, 140592906050976}}) = 0
> [pid 6068] read(8, "\1\0\0\0\0\0\0\0", 8) = 8
> [pid 6068] poll([{fd=9, events=POLLIN}, {fd=8, events=POLLIN|POLLPRI}],
> 2, 1000) = 1 ([{fd=8, revents=POLLIN}])
> [pid 6068] timerfd_gettime(8, , {it_interval={0, 20000000},
> it_value={0, 140592906050976}}) = 0
> [pid 6068] read(8, "\1\0\0\0\0\0\0\0", 8) = 8
>
> fd 8 is:
>
> lrwx------ 1 root root 64 Nov 17 15:27 /proc/6025/fd/8 ->
> anon_inode:[timerfd]
>
>
> # cat /proc/6025/stack
> [<ffffffff941d60e9>] poll_schedule_timeout+0x49/0x70
> [<ffffffff941d76c7>] do_sys_poll+0x3d7/0x590
> [<ffffffff941d78bc>] do_restart_poll+0x3c/0x70
> [<ffffffff9408e7ff>] sys_restart_syscall+0x1f/0x30
> [<ffffffff9463f1ee>] system_call_fastpath+0x12/0x71
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> Any ideas how to debug this?

fd 8 is probably not really interesting. That looks like a interval
timer firing periodically. So it probably waits for fd 9 ...

Thanks,

tglx
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