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Subject: Re: KASAN: null-ptr-deref Write in kthread_use_mm
To:     syzbot <syzbot+b57abf7ee60829090495@syzkaller.appspotmail.com>,
        io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, mingo@kernel.org, mingo@redhat.com,
        peterz@infradead.org, rostedt@goodmis.org,
        syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk,
        will@kernel.org
References: <00000000000008604f05b31e6867@google.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <298f1180-ab14-d08e-dcd2-3e4bbbc1e90a@kernel.dk>
Date:   Mon, 2 Nov 2020 08:19:29 -0700
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On 11/2/20 4:54 AM, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    4e78c578 Add linux-next specific files for 20201030
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=148969d4500000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=83318758268dc331
> dashboard link: https://syzkaller.appspot.com/bug?extid=b57abf7ee60829090495
> compiler:       gcc (GCC) 10.1.0-syz 20200507
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17e1346c500000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1388fbca500000
> 
> The issue was bisected to:
> 
> commit 4d004099a668c41522242aa146a38cc4eb59cb1e
> Author: Peter Zijlstra <peterz@infradead.org>
> Date:   Fri Oct 2 09:04:21 2020 +0000
> 
>     lockdep: Fix lockdep recursion

That bisection definitely isn't correct. But I'll take a look at the issue.

-- 
Jens Axboe