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Subject: Re: inconsistent lock state in xa_destroy
To:     Matthew Wilcox <willy@infradead.org>
Cc:     syzbot <syzbot+cdcbdc0bd42e559b52b9@syzkaller.appspotmail.com>,
        io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
        viro@zeniv.linux.org.uk
References: <00000000000045ac4605b12a1720@google.com>
 <de842e7f-fa50-193b-b1d7-c573e515ef8b@kernel.dk>
 <20201008150518.GG20115@casper.infradead.org>
 <ecfb657e-91fe-5e53-20b7-63e9e6105986@kernel.dk>
 <20201008152844.GI20115@casper.infradead.org>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <774b6b47-7c19-f2e9-588d-0f6bb363a2d7@kernel.dk>
Date:   Thu, 8 Oct 2020 09:32:06 -0600
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On 10/8/20 9:28 AM, Matthew Wilcox wrote:
> On Thu, Oct 08, 2020 at 09:06:56AM -0600, Jens Axboe wrote:
>> On 10/8/20 9:05 AM, Matthew Wilcox wrote:
>>> On Thu, Oct 08, 2020 at 09:01:57AM -0600, Jens Axboe wrote:
>>>> On 10/8/20 9:00 AM, syzbot wrote:
>>>>> Hello,
>>>>>
>>>>> syzbot found the following issue on:
>>>>>
>>>>> HEAD commit:    e4fb79c7 Add linux-next specific files for 20201008
>>>>> git tree:       linux-next
>>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=12555227900000
>>>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=568d41fe4341ed0f
>>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=cdcbdc0bd42e559b52b9
>>>>> compiler:       gcc (GCC) 10.1.0-syz 20200507
>>>>>
>>>>> 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+cdcbdc0bd42e559b52b9@syzkaller.appspotmail.com
>>>>
>>>> Already pushed out a fix for this, it's really an xarray issue where it just
>>>> assumes that destroy can irq grab the lock.
>>>
>>> ... nice of you to report the issue to the XArray maintainer.
>>
>> This is from not even 12h ago, 10h of which I was offline. It wasn't on
>> the top of my list of priority items to tackle this morning, but it
>> is/was on the list.
> 
> How's this?

Looks like that'll do the trick in avoiding similar future lockdep
splats for xa_destroy().

-- 
Jens Axboe