commit 2ba136daa3ae1e881c9f586f283fcaa164767dce
author Tony Battersby <tonyb@cybernetics.com> Fri Aug 22 15:53:35 2014 -0400
committer Jens Axboe <axboe@fb.com> Fri Aug 22 15:04:33 2014 -0500
tree e10d432b6e8fe38d768aa3f9ba3c136ff9756ad7
parent 6f4a16266fb3e58cd3e200eab51d2220ef92d604

fix regression in SCSI_IOCTL_SEND_COMMAND

blk_rq_set_block_pc() memsets rq->cmd to 0, so it should come
immediately after blk_get_request() to avoid overwriting the
user-supplied CDB.  Also check for failure to allocate rq.

Fixes: f27b087b81b7 ("block: add blk_rq_set_block_pc()")
Cc: <stable@vger.kernel.org> # 3.16.x
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/scsi_ioctl.c

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 1d78e6c..5dd477b 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -456,6 +456,11 @@
 	}
 
 	rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);
+	if (!rq) {
+		err = -ENOMEM;
+		goto error;
+	}
+	blk_rq_set_block_pc(rq);
 
 	cmdlen = COMMAND_SIZE(opcode);
 
@@ -509,7 +514,6 @@
 	memset(sense, 0, sizeof(sense));
 	rq->sense = sense;
 	rq->sense_len = 0;
-	blk_rq_set_block_pc(rq);
 
 	blk_execute_rq(q, disk, rq, 0);
 
@@ -529,7 +533,8 @@
 	
 error:
 	kfree(buffer);
-	blk_put_request(rq);
+	if (rq)
+		blk_put_request(rq);
 	return err;
 }
 EXPORT_SYMBOL_GPL(sg_scsi_ioctl);