Patch "scsi: sg: don't return bogus Sg_requests" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    scsi: sg: don't return bogus Sg_requests

to the 4.4-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-sg-don-t-return-bogus-sg_requests.patch
and it can be found in the queue-4.4 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 48ae8484e9fc324b4968d33c585e54bc98e44d61 Mon Sep 17 00:00:00 2001
From: Johannes Thumshirn <jthumshirn@suse.de>
Date: Wed, 10 May 2017 09:53:40 +0200
Subject: scsi: sg: don't return bogus Sg_requests

From: Johannes Thumshirn <jthumshirn@suse.de>

commit 48ae8484e9fc324b4968d33c585e54bc98e44d61 upstream.

If the list search in sg_get_rq_mark() fails to find a valid request, we
return a bogus element. This then can later lead to a GPF in
sg_remove_scat().

So don't return bogus Sg_requests in sg_get_rq_mark() but NULL in case
the list search doesn't find a valid request.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Doug Gilbert <dgilbert@interlog.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Doug Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/sg.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -2074,11 +2074,12 @@ sg_get_rq_mark(Sg_fd * sfp, int pack_id)
 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
 			resp->done = 2;	/* guard against other readers */
-			break;
+			write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
+			return resp;
 		}
 	}
 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
-	return resp;
+	return NULL;
 }
 
 /* always adds to end of list */


Patches currently in stable-queue which might be from jthumshirn@suse.de are

queue-4.4/scsi-sg-don-t-return-bogus-sg_requests.patch