Commit 5ae17501 authored by Ewan D. Milne's avatar Ewan D. Milne Committed by Martin K. Petersen
Browse files

scsi: core: Avoid leaving shost->last_reset with stale value if EH does not run 

The changes to issue the abort from the scmd->abort_work instead of the EH
thread introduced a problem if eh_deadline is used.  If aborting the
command(s) is successful, and there are never any scmds added to the
shost->eh_cmd_q, there is no code path which will reset the ->last_reset
value back to zero.

The effect of this is that after a successful abort with no EH thread
activity, a subsequent timeout, perhaps a long time later, might
immediately be considered past a user-set eh_deadline time, and the host
will be reset with no attempt at recovery.

Fix this by resetting ->last_reset back to zero in scmd_eh_abort_handler()
if it is determined that the EH thread will not run to do this.

Thanks to Gopinath Marappan for investigating this problem.

Link: https://lore.kernel.org/r/20211029194311.17504-2-emilne@redhat.com


Fixes: e494f6a7 ("[SCSI] improved eh timeout handler")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarEwan D. Milne <emilne@redhat.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 5f7cf82c

drivers/scsi/hosts.c

+1 −0
Original line number Diff line number Diff line
@@ -387,6 +387,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) 
	shost->shost_state = SHOST_CREATED;

	INIT_LIST_HEAD(&shost->__devices);

	INIT_LIST_HEAD(&shost->__targets);

	INIT_LIST_HEAD(&shost->eh_abort_list);

	INIT_LIST_HEAD(&shost->eh_cmd_q);

	INIT_LIST_HEAD(&shost->starved_list);

	init_waitqueue_head(&shost->host_wait);

drivers/scsi/scsi_error.c

+25 −0
Original line number Diff line number Diff line
@@ -133,6 +133,23 @@ static bool scsi_eh_should_retry_cmd(struct scsi_cmnd *cmd) 
	return true;

}



static void scsi_eh_complete_abort(struct scsi_cmnd *scmd, struct Scsi_Host *shost)

{

	unsigned long flags;



	spin_lock_irqsave(shost->host_lock, flags);

	list_del_init(&scmd->eh_entry);

	/*

	 * If the abort succeeds, and there is no further

	 * EH action, clear the ->last_reset time.

	 */

	if (list_empty(&shost->eh_abort_list) &&

	    list_empty(&shost->eh_cmd_q))

		if (shost->eh_deadline != -1)

			shost->last_reset = 0;

	spin_unlock_irqrestore(shost->host_lock, flags);

}



/**

 * scmd_eh_abort_handler - Handle command aborts

 * @work:	command to be aborted.
@@ -150,6 +167,7 @@ scmd_eh_abort_handler(struct work_struct *work) 
		container_of(work, struct scsi_cmnd, abort_work.work);

	struct scsi_device *sdev = scmd->device;

	enum scsi_disposition rtn;

	unsigned long flags;



	if (scsi_host_eh_past_deadline(sdev->host)) {

		SCSI_LOG_ERROR_RECOVERY(3,
@@ -173,12 +191,14 @@ scmd_eh_abort_handler(struct work_struct *work) 
				SCSI_LOG_ERROR_RECOVERY(3,

					scmd_printk(KERN_WARNING, scmd,

						    "retry aborted command\n"));

				scsi_eh_complete_abort(scmd, sdev->host);

				scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);

				return;

			} else {

				SCSI_LOG_ERROR_RECOVERY(3,

					scmd_printk(KERN_WARNING, scmd,

						    "finish aborted command\n"));

				scsi_eh_complete_abort(scmd, sdev->host);

				scsi_finish_command(scmd);

				return;

			}
@@ -191,6 +211,9 @@ scmd_eh_abort_handler(struct work_struct *work) 
		}

	}



	spin_lock_irqsave(sdev->host->host_lock, flags);

	list_del_init(&scmd->eh_entry);

	spin_unlock_irqrestore(sdev->host->host_lock, flags);

	scsi_eh_scmd_add(scmd);

}
@@ -221,6 +244,8 @@ scsi_abort_command(struct scsi_cmnd *scmd) 
	spin_lock_irqsave(shost->host_lock, flags);

	if (shost->eh_deadline != -1 && !shost->last_reset)

		shost->last_reset = jiffies;

	BUG_ON(!list_empty(&scmd->eh_entry));

	list_add_tail(&scmd->eh_entry, &shost->eh_abort_list);

	spin_unlock_irqrestore(shost->host_lock, flags);



	scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;

drivers/scsi/scsi_lib.c

+1 −0
Original line number Diff line number Diff line
@@ -1143,6 +1143,7 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) 
	cmd->sense_buffer = buf;

	cmd->prot_sdb = prot;

	cmd->flags = flags;

	INIT_LIST_HEAD(&cmd->eh_entry);

	INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);

	cmd->jiffies_at_alloc = jiffies_at_alloc;

	cmd->retries = retries;

include/scsi/scsi_cmnd.h

+1 −1
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ enum scsi_cmnd_submitter { 
struct scsi_cmnd {

	struct scsi_request req;

	struct scsi_device *device;

	struct list_head eh_entry; /* entry for the host eh_cmd_q */

	struct list_head eh_entry; /* entry for the host eh_abort_list/eh_cmd_q */

	struct delayed_work abort_work;



	struct rcu_head rcu;

include/scsi/scsi_host.h

+1 −0
Original line number Diff line number Diff line
@@ -551,6 +551,7 @@ struct Scsi_Host { 


	struct mutex		scan_mutex;/* serialize scanning activity */



	struct list_head	eh_abort_list;

	struct list_head	eh_cmd_q;

	struct task_struct    * ehandler;  /* Error recovery thread. */

	struct completion     * eh_action; /* Wait for specific actions on the