> From: Greg KH <greg@xxxxxxxxx> > Sent: Tuesday, April 17, 2018 03:34 > 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? > 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