On Fri, Nov 12, 2021 at 08:46:43PM +0200, Nikolay Borisov wrote: > [CC'ing Omar as Kyber is mentioned] > > On 12.11.21 г. 20:06, Chris Murphy wrote: > > On Fri, Nov 12, 2021 at 1:55 AM Nikolay Borisov <nborisov@xxxxxxxx> wrote: > >> > >> > >> > >> On 11.11.21 г. 22:57, Chris Murphy wrote: > >>> On Thu, Nov 11, 2021 at 3:24 PM Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote: > >>>> > >>>> Soon after logging in and launching some apps, I get a hang. Although > >>>> there's lots of btrfs stuff in the call traces, I think we're stuck in > >>>> writeback so everything else just piles up and it all hangs > >>>> indefinitely. > >>>> > >>>> Happening since at least > >>>> 5.16.0-0.rc0.20211109gitd2f38a3c6507.9.fc36.x86_64 and is still happening with > >>>> 5.16.0-0.rc0.20211111gitdebe436e77c7.11.fc36.x86_64 > >>>> > >>>> Full dmesg including sysrq+w when the journal becomes unresponsive and > >>>> then a bunch of block tasks > 120s roll in on their own. > >>>> > >>>> https://bugzilla-attachments.redhat.com/attachment.cgi?id=1841283 > >>> > >> > >> > >> The btrfs traces in this one doesn't look interesting, what's > >> interesting is you have a bunch of tasks, including btrfs transaction > >> commit which are stuck waiting to get a tag from the underlying block > >> device - blk_mq_get_tag function. This indicates something's going on > >> with the underlying block device. > > > > Well the hang doesn't ever happen with 5.14.x or 5.15.x kernels, only > > the misc-next (Fedora rc0) kernels. And also I just discovered that > > it's not happening (or not as quickly) with IO scheduler none. I've > > been using kyber and when I switch back to it, the hang happens almost > > immediately. > > Well I see a bunch of WARN_ONs being triggered, so is it possible that > this is some issue which is going to be fixed in some future RC ? Omar > what steps should be taken to try and debug this from the Kyber side of > things? Chris, does this happen on upstream 5.16-rc1? I couldn't reproduce it.
