On Wed, 2017-11-08 at 09:12 +0100, Hannes Reinecke wrote: > You know, this actually looks like the same issue I'm chasing with iser; > we have a customer who regularly sees lockups during scanning. > As it turns out, iser is calling scsi_device_del() from the RX thread. > Which in turn needs to call async_synchronize(). > If a disk scan is running at the same time we have a nice deadlock, as > the RX thread can't move forward before aynch_synchronize() returns, > which it'll never do as the scan cannot complete. > I've tried to fix that by having the async probing only waiting for that > particular instance (look for patch 'sd: use async_probe cookie to avoid > deadlocks'), but this wasn't greeted with much enthusiasm. Hello Hannes, Since I applied Roman Penyaev's patch "[PATCH 1/1] [RFC] blk-mq: fix queue stalling on shared hctx restart" I have not been able to reproduce this hang. I will let you know if I would run into this hang again. Bart.
