lkml.org 
[lkml]   [2017]   [Dec]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: BUG: workqueue lockup (2)
From
Date
syzbot wrote:
>
> syzkaller has found reproducer for the following crash on
> f3b5ad89de16f5d42e8ad36fbdf85f705c1ae051

"BUG: workqueue lockup" is not a crash.

> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
> C reproducer is attached
> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> for information about syzkaller reproducers
>
>
> BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 37s!
> BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=-20 stuck for 32s!
> Showing busy workqueues and worker pools:
> workqueue events: flags=0x0
> pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256
> pending: cache_reap
> workqueue events_power_efficient: flags=0x80
> pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256
> pending: neigh_periodic_work, do_cache_clean
> workqueue mm_percpu_wq: flags=0x8
> pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256
> pending: vmstat_update
> workqueue kblockd: flags=0x18
> pwq 3: cpus=1 node=0 flags=0x0 nice=-20 active=1/256
> pending: blk_timeout_work

You gave up too early. There is no hint for understanding what was going on.
While we can observe "BUG: workqueue lockup" under memory pressure, there is
no hint like SysRq-t and SysRq-m. Thus, I can't tell something is wrong.

At least you need to confirm that lockup lasts for a few minutes. Otherwise,
this might be just overstressing. (According to repro.c , 12 threads are
created and soon SEGV follows? According to above message, only 2 CPUs?
Triggering SEGV suggests memory was low due to saving coredump?)

\
 
 \ /
  Last update: 2017-12-19 15:28    [W:0.881 / U:0.580 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site