On 8/29/22 02:14, Ming Lei wrote:
On Mon, Aug 22, 2022 at 6:05 AM Bart Van Assche <bvanassche@xxxxxxx> wrote:
Since a device, target or host reference may be held when scsi_remove_host()
or scsi_remove_target() is called and since te patch series "Call
blk_mq_free_tag_set() earlier" makes these functions wait until all references
are gone, that patch series may trigger a deadlock. Hence this request to
revert the patch series "Call blk_mq_free_tag_set() earlier".
Care to share the deadlock details? Such as dmesg log or theory behind.
Hi Ming,
Details of two different deadlock scenarios are available here:
* [syzbot] INFO: task hung in scsi_remove_host
(https://lore.kernel.org/all/000000000000b5187d05e6c08086@xxxxxxxxxx/).
* https://lore.kernel.org/all/Yv%2FMKymRC9O04Nqu@xxxxxxxxxx/. The link
[2] in this email includes a call trace and instructions for reproducing
this issue. My root cause analysis of this deadlock is available here:
https://lore.kernel.org/all/27d0dde8-344c-1dd0-cc26-0e10c4e1f296@xxxxxxx/.
Thanks,
Bart.
