On Wed, Mar 20, 2019 at 01:58:06PM +0100, Jan Kara wrote: > Hello, > > commit 310ca162d77 "block/loop: Use global lock for ioctl() operation." has > been pushed to multiple stable trees. This patch is a part of larger series > that overhauls the locking inside loopback device upstream and for 4.4, > 4.9, and 4.14 stable trees only this patch from the series is applied. Our > testing now has shown [1] that the patch alone makes present deadlocks > inside loopback driver more likely (the openqa test in our infrastructure > didn't hit the deadlock before whereas with the new kernel it hits it > reliably every time). So I would suggest we revert 310ca162d77 from 4.4, > 4.9, and 4.14 kernels. > > Another option would be to backport other locking fixes for the loop > device but honestly I don't think that's a stable material - never heard > of real users hitting problems, only syzkaller could, and we are still > fixing up some small glitches resulting from that rework... > > Honza > > [1] https://bugzilla.suse.com/show_bug.cgi?id=1129739 Note, I do not have access to that bug report :(
