Re: WARNING in get_unlocked_entry

[Dmitry Vyukov]

On Wed, Oct 31, 2018 at 8:18 PM, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> On Wed, Oct 31, 2018 at 10:46:19AM +0100, Dmitry Vyukov wrote:
>> On Wed, Oct 31, 2018 at 4:18 AM, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
>> > On Tue, Oct 30, 2018 at 08:00:03AM -0700, syzbot wrote:
>> >> syzbot found the following crash on:
>> >>
>> >> HEAD commit:    4b42745211af Merge tag 'armsoc-soc' of git://git.kernel.or..
>> >> git tree:       upstream
>> >> console output: https://syzkaller.appspot.com/x/log.txt?x=1187d06d400000
>> >> kernel config:  https://syzkaller.appspot.com/x/.config?x=93932074d01b4a5
>> >> dashboard link: https://syzkaller.appspot.com/bug?extid=4fd0c066d82852499145
>> >> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
>> >>
>> >> Unfortunately, I don't have any reproducer for this crash yet.
>> >
>> > Hmmpf.  Would have been nice if syzbot had caught this during its tests
>> > of the -next tree ...
>>
>> What -next tree do you mean? If it satisfies the criteria we can add it:
>> https://github.com/google/syzkaller/issues/592
>
> I meant linux-next, as in the merge of everybody's -next trees.  Reading
> that bug, it seems outside your scope for now ;-(


We do test linux-next:
https://syzkaller.appspot.com/#managers
But this crash happened only once across all trees and machines. So it
just looks too elusive (subtle race?) to be reliably spotted in
linux-next.