Patch "scsi: zero per-cmd private driver data for each MQ I/O" has been added to the 4.11-stable tree

[<gregkh@linuxfoundation.org>]

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

    scsi: zero per-cmd private driver data for each MQ I/O

to the 4.11-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:
     scsi-zero-per-cmd-private-driver-data-for-each-mq-i-o.patch
and it can be found in the queue-4.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 1bad6c4a57efda0d5f5bf8a2403b21b1ed24875c Mon Sep 17 00:00:00 2001
From: Long Li <longli@microsoft.com>
Date: Thu, 18 May 2017 15:40:05 -0700
Subject: scsi: zero per-cmd private driver data for each MQ I/O

From: Long Li <longli@microsoft.com>

commit 1bad6c4a57efda0d5f5bf8a2403b21b1ed24875c upstream.

In lower layer driver's (LLD) scsi_host_template, the driver may
optionally ask SCSI to allocate its private driver memory for each
command, by specifying cmd_size. This memory is allocated at the end of
scsi_cmnd by SCSI.  Later when SCSI queues a command, the LLD can use
scsi_cmd_priv to get to its private data.

Some LLD, e.g. hv_storvsc, doesn't clear its private data before use. In
this case, the LLD may get to stale or uninitialized data in its private
driver memory. This may result in unexpected driver and hardware
behavior.

Fix this problem by also zeroing the private driver memory before
passing them to LLD.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Reviewed-by: KY Srinivasan <kys@microsoft.com>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/scsi_lib.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1850,7 +1850,7 @@ static int scsi_mq_prep_fn(struct reques
 
 	/* zero out the cmd, except for the embedded scsi_request */
 	memset((char *)cmd + sizeof(cmd->req), 0,
-		sizeof(*cmd) - sizeof(cmd->req));
+		sizeof(*cmd) - sizeof(cmd->req) + shost->hostt->cmd_size);
 
 	req->special = cmd;
 


Patches currently in stable-queue which might be from longli@microsoft.com are

queue-4.11/scsi-zero-per-cmd-private-driver-data-for-each-mq-i-o.patch