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. -- Chris Murphy
