On 9/12/26 4:04 AM, Jia Jia wrote: > vhost_scsi_send_evt() is called with the event virtqueue mutex held. > If the worker is gone, the fallback currently calls > vhost_scsi_complete_events(), which tries to acquire the same mutex again > and deadlocks the caller. > > Split event completion into a helper for callers that already hold the > mutex and a locking wrapper for the event worker. Use the helper on the > fallback path. > > Link: https://lore.kernel.org/all/[email protected]/ > Fixes: b1b2ce58ed23 ("vhost-scsi: Handle vhost_vq_work_queue failures for > events") > Signed-off-by: Jia Jia <[email protected]> > --- > Sashiko AI flagged this while reviewing > the vhost-scsi event queue fix. > This is a pre-existing self-deadlock. It was reproduced in a follow-up test. > > Trigger: vq->worker == NULL. vhost_vq_work_queue() then returns false, > and a subsequent vhost_scsi_do_plug() call deadlocks. I do not know what > normal condition gets us here; the normal vhost-scsi worker detach/reset > paths do not reach this code. The only reproduction I could come up with > was killing the vhost-scsi worker. This still looks like a low-probability > condition.
Reviewed-by: Mike Christie <[email protected]>
