Re: BUG: workqueue lockup (4)

Re: BUG: workqueue lockup (4)

[Dmitry Vyukov]

On Sun, Oct 7, 2018 at 2:15 PM, syzbot
<syzbot+08116743f8ad6f9a6de7@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    c1d84a1b42ef Merge git://git.kernel.org/pub/scm/linux/kern..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14c5f491400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c0af03fe452b65fb
> dashboard link: https://syzkaller.appspot.com/bug?extid=08116743f8ad6f9a6de7
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14514a6e400000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1025ebb9400000

The reproducer seems to be all about rtc. So +rtc maintainers.

> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+08116743f8ad6f9a6de7@syzkaller.appspotmail.com
>
> BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 204s!
> Showing busy workqueues and worker pools:
> workqueue events: flags=0x0
>   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=4/256
>     in-flight: 14:rtc_timer_do_work
>     pending: vmstat_shepherd, cache_reap, check_corruption
> workqueue events_power_efficient: flags=0x80
>   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
>     pending: do_cache_clean
> workqueue mm_percpu_wq: flags=0x8
>   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
>     pending: vmstat_update
> workqueue kacpi_notify: flags=0x0
>   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1
>     pending: acpi_os_execute_deferred
> pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=204s workers=2 idle: 2683
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this bug report. See:
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> syzbot.
> syzbot can test patches for this bug, for details see:
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>
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Re: BUG: workqueue lockup (4)

[Alexandre Belloni]

Hi,

On 07/10/2018 14:18:31+0200, Dmitry Vyukov wrote:
> On Sun, Oct 7, 2018 at 2:15 PM, syzbot
> <syzbot+08116743f8ad6f9a6de7@syzkaller.appspotmail.com> wrote:
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    c1d84a1b42ef Merge git://git.kernel.org/pub/scm/linux/kern..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=14c5f491400000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=c0af03fe452b65fb
> > dashboard link: https://syzkaller.appspot.com/bug?extid=08116743f8ad6f9a6de7
> > compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14514a6e400000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1025ebb9400000
> 
> The reproducer seems to be all about rtc. So +rtc maintainers.
> 

It seems to be that bug:
http://patchwork.ozlabs.org/patch/898552/

I'm pretty sure the fix is not correct though and didn't have the time
to work on a proper fix.

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

[rtc] Re: BUG: workqueue lockup (4)

[Eric Biggers]

On Sun, Oct 07, 2018 at 09:39:18PM +0200, Alexandre Belloni wrote:
> Hi,
> 
> On 07/10/2018 14:18:31+0200, Dmitry Vyukov wrote:
> > On Sun, Oct 7, 2018 at 2:15 PM, syzbot
> > <syzbot+08116743f8ad6f9a6de7@syzkaller.appspotmail.com> wrote:
> > > Hello,
> > >
> > > syzbot found the following crash on:
> > >
> > > HEAD commit:    c1d84a1b42ef Merge git://git.kernel.org/pub/scm/linux/kern..
> > > git tree:       upstream
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=14c5f491400000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=c0af03fe452b65fb
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=08116743f8ad6f9a6de7
> > > compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14514a6e400000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1025ebb9400000
> > 
> > The reproducer seems to be all about rtc. So +rtc maintainers.
> > 
> 
> It seems to be that bug:
> http://patchwork.ozlabs.org/patch/898552/
> 
> I'm pretty sure the fix is not correct though and didn't have the time
> to work on a proper fix.
> 

Is there any plan to actually fix this?  Because this bug is still open, syzbot
isn't able to report "workqueue lockup" bugs elsewhere in the kernel.

- Eric

Re: [rtc] Re: BUG: workqueue lockup (4)

[Alexandre Belloni]

On 10/06/2019 16:49:59-0700, Eric Biggers wrote:
> On Sun, Oct 07, 2018 at 09:39:18PM +0200, Alexandre Belloni wrote:
> > Hi,
> > 
> > On 07/10/2018 14:18:31+0200, Dmitry Vyukov wrote:
> > > On Sun, Oct 7, 2018 at 2:15 PM, syzbot
> > > <syzbot+08116743f8ad6f9a6de7@syzkaller.appspotmail.com> wrote:
> > > > Hello,
> > > >
> > > > syzbot found the following crash on:
> > > >
> > > > HEAD commit:    c1d84a1b42ef Merge git://git.kernel.org/pub/scm/linux/kern..
> > > > git tree:       upstream
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=14c5f491400000
> > > > kernel config:  https://syzkaller.appspot.com/x/.config?x=c0af03fe452b65fb
> > > > dashboard link: https://syzkaller.appspot.com/bug?extid=08116743f8ad6f9a6de7
> > > > compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> > > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14514a6e400000
> > > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1025ebb9400000
> > > 
> > > The reproducer seems to be all about rtc. So +rtc maintainers.
> > > 
> > 
> > It seems to be that bug:
> > http://patchwork.ozlabs.org/patch/898552/
> > 
> > I'm pretty sure the fix is not correct though and didn't have the time
> > to work on a proper fix.
> > 
> 
> Is there any plan to actually fix this?  Because this bug is still open, syzbot
> isn't able to report "workqueue lockup" bugs elsewhere in the kernel.
> 

This is still on my radar.

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com