Re: kernel panics with 4.14.X versions

[Amir Goldstein]

On Tue, Apr 17, 2018 at 1:33 PM, Greg KH <greg@xxxxxxxxx> wrote:
> On Mon, Apr 16, 2018 at 09:10:35PM +0000, Dexuan Cui wrote:
>> > From: Jan Kara <jack@xxxxxxx>
>> > Sent: Monday, April 16, 2018 07:41
>> > ...
>> > How easily can you hit this? Are you able to run debug kernels / inspect
>> > crash dumps when the issue occurs? Also testing with the latest mainline
>> > kernel (4.16) would be welcome whether this isn't just an issue with the
>> > backport of fsnotify fixes from Miklos.
>>
>> It's not easy for us to reproduce the fsnotify() lockup issue, and actually
>> we still don't have an easy & reliable way to reproduce it.
>>
>> According to our tests, v4.16 doesn't have the issue.
>> And v4.15 doesn't have the issue either, if I recall correctly.
>> I only know the issue happens to v4.14.x and 4.13.x kernels
>
> Any chance to run 'git bisect' between 4.14 and 4.15 to find the fix?
>

Looking at the changes between 4.14 and 4.15, that are not in 4.14.32,
the only viable suspects are:
9cf90cef362d fsnotify: Protect bail out path of fsnotify_add_mark_locked()
properly
3427ce715541 fsnotify: clean up fsnotify()

Both don't claim to fix a known issue.
Both look like they could be applied cleanly to 4.14.y.

Thanks,
Amir.