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Patch "53c700: fix BUG on untagged commands" has been added to the 4.6-stable tree

PATCH [email protected] 1 participant 1 message Jul 25, 2016

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This is a note to let you know that I've just added the patch titled

53c700: fix BUG on untagged commands

to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     53c700-fix-bug-on-untagged-commands.patch

and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 8beb330044d0d1878c7b92290e91c0b889e92633 Mon Sep 17 00:00:00 2001

From: James Bottomley <[email protected]>
Date: Mon, 13 Jun 2016 22:00:07 -0700
Subject: 53c700: fix BUG on untagged commands

From: James Bottomley <[email protected]>

commit 8beb330044d0d1878c7b92290e91c0b889e92633 upstream.

The untagged command case in the 53c700 driver has been broken since host wide tags were enabled because the replaced scsi_find_tag() function had a special case for the tag value SCSI_NO_TAG to retrieve sdev->current_cmnd. The replacement function scsi_host_find_tag() has no such special case and returns NULL causing untagged commands to trigger a BUG() in the driver. Inspection shows that the 53c700 is the only driver using this SCSI_NO_TAG case, so a local fix in the driver suffices to fix this problem globally.

---
 drivers/scsi/53c700.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/scsi/53c700.c +2 -2
@@ -1122,7 +1122,7 @@ process_script_interrupt(__u32 dsps, __u
 		} else {
 			struct scsi_cmnd *SCp;
 
-			SCp = scsi_host_find_tag(SDp->host, SCSI_NO_TAG);
+			SCp = SDp->current_cmnd;
 			if(unlikely(SCp == NULL)) {
 				sdev_printk(KERN_ERR, SDp,
 					"no saved request for untagged cmd\n");
@@ -1826,7 +1826,7 @@ NCR_700_queuecommand_lck(struct scsi_cmn
 		       slot->tag, slot);
 	} else {
 		slot->tag = SCSI_NO_TAG;
-		/* must populate current_cmnd for scsi_host_find_tag to work */
+		/* save current command for reselection */
 		SCp->device->current_cmnd = SCp;
 	}
 	/* sanity check: some of the commands generated by the mid-layer

Patches currently in stable-queue which might be from [email protected] are

queue-4.6/scsi-fix-race-between-simultaneous-decrements-of-host_failed.patch queue-4.6/53c700-fix-bug-on-untagged-commands.patch