Re: [syzbot] possible deadlock in throtl_pending_timer_fn

[Ming Lei <ming.lei-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Tue, Mar 29, 2022 at 07:52:57PM -0700, syzbot wrote:
> > On Wed, Mar 30, 2022 at 5:23 AM syzbot
> > <syzbot+934ebb67352c8a490bf3-Pl5Pbv+GP7P466ipTTIvnc23WoclnBCfAL8bYrjMMd8@public.gmane.org> wrote:
> >>
> >> Hello,
> >>
> >> syzbot found the following issue on:
> >>
> >> HEAD commit:    cb7cbaae7fd9 Merge tag 'drm-next-2022-03-25' of git://anon..
> >> git tree:       upstream
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=17ef8b43700000
> >> kernel config:  https://syzkaller.appspot.com/x/.config?x=7094767cefc58fb9
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=934ebb67352c8a490bf3
> >> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> >>
> >> Unfortunately, I don't have any reproducer for this issue yet.
> >>
> >> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> >> Reported-by: syzbot+934ebb67352c8a490bf3-Pl5Pbv+GP7P466ipTTIvnc23WoclnBCfAL8bYrjMMd8@public.gmane.org
> >
> > #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
> 
> This crash does not have a reproducer. I cannot test it.

This one is triggered in case of memory allocation failure, especially blkg_free()
is called from blkg_alloc() directly. That is why it is hard to reproduce, and it
is one old issue.


Thanks,
Ming