From: Greg KH greg@kroah.com Sent: Tuesday, April 17, 2018 03:34 On Mon, Apr 16, 2018 at 09:10:35PM +0000, Dexuan Cui wrote:
From: Jan Kara jack@suse.cz 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? greg k-h
Sorry, I'm afraid not. It was only reproducible in a customer VM with a specific workload and it took days to hit the issue. The customer VM doesn't exist any more. And we even can't find a way to reproduce the issue with fio tests + programs that test fsnotify().
-- Dexuan