From: Uday Shankar ushankar@purestorage.com
[ Upstream commit 2331ce6126be8864b39490e705286b66e2344aac ]
Userspace can currently write to sysfs to transition sdev_state to RUNNING or OFFLINE from any source state. This causes issues because proper transitioning out of some states involves steps besides just changing sdev_state, so allowing userspace to change sdev_state regardless of the source state can result in inconsistencies; e.g. with ISCSI we can end up with sdev_state == SDEV_RUNNING while the device queue is quiesced. Any task attempting I/O on the device will then hang, and in more recent kernels, iscsid will hang as well.
More detail about this bug is provided in my first attempt:
https://groups.google.com/g/open-iscsi/c/PNKca4HgPDs/m/CXaDkntOAQAJ
Link: https://lore.kernel.org/r/20220924000241.2967323-1-ushankar@purestorage.com Signed-off-by: Uday Shankar ushankar@purestorage.com Suggested-by: Mike Christie michael.christie@oracle.com Reviewed-by: Hannes Reinecke hare@suse.de Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/scsi_sysfs.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 920aae661c5b..774864b54b97 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -816,6 +816,14 @@ store_state_field(struct device *dev, struct device_attribute *attr, }
mutex_lock(&sdev->state_mutex); + switch (sdev->sdev_state) { + case SDEV_RUNNING: + case SDEV_OFFLINE: + break; + default: + mutex_unlock(&sdev->state_mutex); + return -EINVAL; + } if (sdev->sdev_state == SDEV_RUNNING && state == SDEV_RUNNING) { ret = 0; } else {