On Wed, Feb 08, 2023 at 06:11:48AM -0500, Emanuele Giuseppe Esposito wrote: > virtio_blk_update_config() calls blk_get_geometry and blk_getlength, > and both functions eventually end up calling bdrv_poll_co when not > running in a coroutine: > - blk_getlength is a co_wrapper_mixed function > - blk_get_geometry calls bdrv_get_geometry -> bdrv_nb_sectors, a > co_wrapper_mixed function too > > Since we are not running in a coroutine, we need to take s->blk > AioContext lock, otherwise bdrv_poll_co will inevitably call > AIO_WAIT_WHILE and therefore try to un unlock() an AioContext lock > that was never acquired. > > RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2167838 > > Steps to reproduce the issue: simply boot a VM with > -object '{"qom-type":"iothread","id":"iothread1"}' \ > -blockdev > '{"driver":"file","filename":"$QCOW2","aio":"native","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}' > \ > -blockdev > '{"node-name":"libvirt-1-format","read-only":false,"cache":{"direct":true,"no-flush":false},"driver":"qcow2","file":"libvirt-1-storage"}' > \ > -device > virtio-blk-pci,iothread=iothread1,drive=libvirt-1-format,id=virtio-disk0,bootindex=1,write-cache=on > > and observe that it will fail not manage to boot with > "qemu_mutex_unlock_impl: Operation not permitted" > > Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com> > --- > hw/block/virtio-blk.c | 5 +++++ > 1 file changed, 5 insertions(+)
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
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