The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5ae17501bc62a49b0b193dcce003f16375f16654 Mon Sep 17 00:00:00 2001
From: "Ewan D. Milne" emilne@redhat.com Date: Fri, 29 Oct 2021 15:43:10 -0400 Subject: [PATCH] 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: e494f6a72839 ("[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
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 17aef936bc90..2cb7163e24cc 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -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); diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 3de03925550e..bdf782d9cb86 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -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; diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index d0b7c6dc74f8..c851c05d6091 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -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; diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index 7958a604f979..29ac40cf1aae 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -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; diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index ae715959f886..ebe059badba0 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -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