Re: [syzbot] possible deadlock in f_getown

[Desmond Cheong Zhi Xi]

On 23/9/21 2:03 am, syzbot wrote:
> syzbot suspects this issue was fixed by commit:
>
> commit f671a691e299f58835d4660d642582bf0e8f6fda
> Author: Desmond Cheong Zhi Xi <desmondcheongzx@xxxxxxxxx>
> Date:   Fri Jul 2 09:18:30 2021 +0000
>
>      fcntl: fix potential deadlocks for &fown_struct.lock
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15fa8017300000
> start commit:   293837b9ac8d Revert "i915: fix remap_io_sg to verify the p..
> git tree:       upstream
> kernel config:  https://syzkaller.appspot.com/x/.config?x=18fade5827eb74f7
> dashboard link: https://syzkaller.appspot.com/bug?extid=8073030e235a5a84dd31
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=171390add00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10050553d00000
>
> If the result looks correct, please mark the issue as fixed by replying with:
>
> #syz fix: fcntl: fix potential deadlocks for &fown_struct.lock
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection

#syz fix: fcntl: fix potential deadlocks for &fown_struct.lock

Think I got jumbled a bit when marking the dups. This bug shares the 
same root cause as [1], and is fixed by the same patch. Nice that Syzbot 
noticed.

Link: https://syzkaller.appspot.com/bug?extid=e6d5398a02c516ce5e70 [1]