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

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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: e494f6a728 ("[SCSI] improved eh timeout handler")
Cc: stable@vger.kernel.org
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Ewan D. Milne 2021-10-29 15:43:10 -04:00 committed by Martin K. Petersen
parent 5f7cf82c1d
commit 5ae17501bc
5 changed files with 29 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/scsi/hosts.c
View File

@ -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);

25
drivers/scsi/scsi_error.c
View File

@ -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;

1
drivers/scsi/scsi_lib.c
View File

@ -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;

2
include/scsi/scsi_cmnd.h
View File

@ -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;

1
include/scsi/scsi_host.h
View File

@ -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