From d555a2abf3481f81303d835046a5ec2c4fb3ca8e Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Fri, 28 Mar 2014 10:50:17 -0700 Subject: [SCSI] Fix spurious request sense in error handling We unconditionally execute scsi_eh_get_sense() to make sure all failed commands that should have sense attached, do. However, the routine forgets that some commands, because of the way they fail, will not have any sense code ... we should not bother them with a REQUEST_SENSE command. Fix this by testing to see if we actually got a CHECK_CONDITION return and skip asking for sense if we don't. Tested-by: Alan Stern Signed-off-by: James Bottomley --- drivers/scsi/scsi_error.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/scsi/scsi_error.c') diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 771c16bfdba..d020149ea8d 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -1157,6 +1157,15 @@ int scsi_eh_get_sense(struct list_head *work_q, __func__)); break; } + if (status_byte(scmd->result) != CHECK_CONDITION) + /* + * don't request sense if there's no check condition + * status because the error we're processing isn't one + * that has a sense code (and some devices get + * confused by sense requests out of the blue) + */ + continue; + SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd, "%s: requesting sense\n", current->comm)); -- cgit v1.2.3-70-g09d2 From 644373a4219add42123df69c8b7ce6a918475ccd Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 28 Mar 2014 10:51:15 -0700 Subject: [SCSI] Fix command result state propagation We're seeing a case where the contents of scmd->result isn't being reset after a SCSI command encounters an error, is resubmitted, times out and then gets handled. The error handler acts on the stale result of the previous error instead of the timeout. Fix this by properly zeroing the scmd->status before the command is resubmitted. Signed-off-by: Alan Stern Signed-off-by: James Bottomley --- drivers/scsi/scsi_error.c | 1 + drivers/scsi/scsi_lib.c | 1 + 2 files changed, 2 insertions(+) (limited to 'drivers/scsi/scsi_error.c') diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index d020149ea8d..2953bfa92da 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -924,6 +924,7 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses, memset(scmd->cmnd, 0, BLK_MAX_CDB); memset(&scmd->sdb, 0, sizeof(scmd->sdb)); scmd->request->next_rq = NULL; + scmd->result = 0; if (sense_bytes) { scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE, diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 7fa54fe51f6..9db097a28a7 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -137,6 +137,7 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) * lock such that the kblockd_schedule_work() call happens * before blk_cleanup_queue() finishes. */ + cmd->result = 0; spin_lock_irqsave(q->queue_lock, flags); blk_requeue_request(q, cmd->request); kblockd_schedule_work(q, &device->requeue_work); -- cgit v1.2.3-70-g09d2 From 7daf480483e60898f30e0a2a84fecada7a7cfac0 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Mon, 31 Mar 2014 16:37:34 +0200 Subject: [SCSI] Fix USB deadlock caused by SCSI error handling USB requires that every command be aborted first before we escalate to reset. In particular, USB will deadlock if we try to reset first before aborting the command. Unfortunately, the flag we use to tell if a command has already been aborted: SCSI_EH_ABORT_SCHEDULED is not cleared properly leading to cases where we can requeue a command with the flag set and proceed immediately to reset if it fails (thus causing USB to deadlock). Fix by clearing the SCSI_EH_ABORT_SCHEDULED flag if it has been set. Which means this will be the second time scsi_abort_command() has been called for the same command. IE the first abort went out, did its thing, but now the same command has timed out again. So this flag gets cleared, and scsi_abort_command() returns FAILED, and _no_ asynchronous abort is being scheduled. scsi_times_out() will then proceed to call scsi_eh_scmd_add(). But as we've cleared the SCSI_EH_ABORT_SCHEDULED flag the SCSI_EH_CANCEL_CMD flag will continue to be set, and the command will be aborted with the main SCSI EH routine. Reported-by: Alan Stern Tested-by: Andreas Reis Signed-off-by: Hannes Reinecke Signed-off-by: James Bottomley --- drivers/scsi/scsi_error.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/scsi/scsi_error.c') diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 2953bfa92da..ad064d2d730 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -189,6 +189,7 @@ scsi_abort_command(struct scsi_cmnd *scmd) /* * Retry after abort failed, escalate to next level. */ + scmd->eh_eflags &= ~SCSI_EH_ABORT_SCHEDULED; SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd, "scmd %p previous abort failed\n", scmd)); -- cgit v1.2.3-70-g09d2 From c69e6f812bab0d5442b40e2f1bfbca48d40bc50b Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Thu, 10 Apr 2014 13:36:11 -0700 Subject: [SCSI] More USB deadlock fixes This patch fixes a corner case in the previous USB Deadlock fix patch (12023e7 [SCSI] Fix USB deadlock caused by SCSI error handling). The scenario is abort command, set flag, abort completes, send TUR, TUR doesn't return, so we now try to abort the TUR, but scsi_abort_eh_cmnd() will skip the abort because the flag is set and move straight to reset. Reviewed-by: Hannes Reinecke Signed-off-by: James Bottomley --- drivers/scsi/scsi_error.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/scsi/scsi_error.c') diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index ad064d2d730..f17aa7aa787 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -921,6 +921,7 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses, ses->prot_op = scmd->prot_op; scmd->prot_op = SCSI_PROT_NORMAL; + scmd->eh_eflags = 0; scmd->cmnd = ses->eh_cmnd; memset(scmd->cmnd, 0, BLK_MAX_CDB); memset(&scmd->sdb, 0, sizeof(scmd->sdb)); -- cgit v1.2.3-70-g09d2