diff options
| author | Maxim Levitsky <mlevitsk@redhat.com> | 2020-12-10 14:59:29 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-12-15 12:52:04 -0500 |
| commit | cfd4e36352d4426221aa94da44a172da1aaa741b (patch) | |
| tree | 882248de2cf2c5dda57f34a8818d19470e076965 /hw/scsi | |
| parent | 835cbd8d44b62217b8774b39e1bfd314750c2c51 (diff) | |
scsi: fix device removal race vs IO restart callback on resume
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 <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20201210125929.1136390-2-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw/scsi')
| -rw-r--r-- | hw/scsi/scsi-bus.c | 4 |
1 files changed, 4 insertions, 0 deletions
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); } |