There is (mostly theoretical) race between removal of a scsi device and scsi_dma_restart_bh.
It used to be easier to hit this race prior to my / Paulo's patch series that added rcu to scsi bus device handling code, but IMHO this race should still be possible to hit, at least in theory. Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1854811 Fix it anyway with a patch that was proposed by Paulo in the above bugzilla. Suggested-by: Paolo Bonzini <pbonz...@redhat.com> Signed-off-by: Maxim Levitsky <mlevi...@redhat.com> --- hw/scsi/scsi-bus.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index b901e701f0..edb5c3492a 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -170,6 +170,8 @@ static void scsi_dma_restart_bh(void *opaque) scsi_req_unref(req); } aio_context_release(blk_get_aio_context(s->conf.blk)); + /* Drop the reference that was acquired in scsi_dma_restart_cb */ + object_unref(OBJECT(s)); } void scsi_req_retry(SCSIRequest *req) @@ -188,6 +190,8 @@ static void scsi_dma_restart_cb(void *opaque, int running, RunState state) } if (!s->bh) { AioContext *ctx = blk_get_aio_context(s->conf.blk); + /* The reference is dropped in scsi_dma_restart_bh.*/ + object_ref(OBJECT(s)); s->bh = aio_bh_new(ctx, scsi_dma_restart_bh, s); qemu_bh_schedule(s->bh); } -- 2.26.2
