linux-brain/drivers/scsi/ibmvscsi
Brian King e8fe98f6ec scsi: ibmvfc: Fix invalid state machine BUG_ON()
[ Upstream commit 15cfef8623a449d40d16541687afd58e78033be3 ]

This fixes an issue hitting the BUG_ON() in ibmvfc_do_work(). When going
through a host action of IBMVFC_HOST_ACTION_RESET, we change the action to
IBMVFC_HOST_ACTION_TGT_DEL, then drop the host lock, and reset the CRQ,
which changes the host state to IBMVFC_NO_CRQ. If, prior to setting the
host state to IBMVFC_NO_CRQ, ibmvfc_init_host() is called, it can then end
up changing the host action to IBMVFC_HOST_ACTION_INIT.  If we then change
the host state to IBMVFC_NO_CRQ, we will then hit the BUG_ON().

Make a couple of changes to avoid this. Leave the host action to be
IBMVFC_HOST_ACTION_RESET or IBMVFC_HOST_ACTION_REENABLE until after we drop
the host lock and reset or reenable the CRQ. Also harden the host state
machine to ensure we cannot leave the reset / reenable state until we've
finished processing the reset or reenable.

Link: https://lore.kernel.org/r/20210413001009.902400-1-tyreld@linux.ibm.com
Fixes: 73ee5d8672 ("[SCSI] ibmvfc: Fix soft lockup on resume")
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
[tyreld: added fixes tag]
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
[mkp: fix comment checkpatch warnings]
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:44:25 +02:00
..
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
ibmvfc.c scsi: ibmvfc: Fix invalid state machine BUG_ON() 2021-05-14 09:44:25 +02:00
ibmvfc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
ibmvscsi.c scsi: ibmvscsi: Fix potential race after loss of transport 2020-11-10 12:37:30 +01:00
ibmvscsi.h SCSI misc on 20190709 2019-07-11 15:14:01 -07:00