On Wed, Aug 19, 2020 at 11:29 AM Vojtech Myslivec <vojtech@xxxxxxxxxxxx> wrote: > > Linux backup1 5.7.0-0.bpo.2-amd64 #1 SMP Debian 5.7.10-1~bpo10+1 Should be new enough; I don't see raid related md changes between 5.7.10 and 5.7.16. I haven't looked at 5.8, but 5.7 is probably recent enough to know if there have been relevant changes in 5.8 that are worth testing. > > - `5.7_profs.txt` > - dump of the whole /proc when the issue happened The problem here I think is that /proc/pid/stack is empty. You might have to hammer on it a bunch of times to get a stack. I can't tell if the sysrq+w is enough information to conclusively tell if this is strictly an md problem or if there's something else going on. But I do see in the sysrq+w evidence of a Btrfs snapshot happening, which will result in a flush of the file system. Since the mdadm raid journal is on two SSDs which should be fast enough to accept the metadata changes before actually doing the flush. -- Chris Murphy
