On 28.06.22 г. 12:08 ч., Dominique MARTINET wrote:
I don't have any good reproducer so it's a bit difficult to specify,
let's start with what I have...
I've got this one VM which has various segfaults all over the place when
starting it with aio=io_uring for its disk as follow:
qemu-system-x86_64 -drive file=qemu/atde-test,if=none,id=hd0,format=raw,cache=none,aio=io_uring \
-device virtio-blk-pci,drive=hd0 -m 8G -smp 4 -serial mon:stdio -enable-kvm
It also happens with virtio-scsi-blk:
-device virtio-scsi-pci,id=scsihw0 \
-drive file=qemu/atde-test,if=none,id=drive-scsi0,format=raw,cache=none,aio=io_uring \
-device scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100
Alternatively change cache=none (O_DIRECT) to cache=writeback (ordinary
buffered writeback path) that way we'll know if it's related to the
iomap-based O_DIRECT code in btrfs.
