On Wed 20-03-19 16:16:28, Greg KH wrote: > 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 :( Sorry, sometimes I hate how paranoid our bugzilla is. I've mirrorred the relevant parts to: https://bugzilla.kernel.org/show_bug.cgi?id=202985 Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
