linux-kernel - [PATCH 3.12 12/39] block: Always check queue limits for cloned requests

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <052bd81382379ccaf002ae7a0c3d4ff6f058428b.1453722244.git.jslaby@suse.cz>
Date:	Mon, 25 Jan 2016 12:49:53 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Hannes Reinecke <hare@...e.de>,
	Mike Snitzer <snitzer@...hat.com>,
	Ewan Milne <emilne@...hat.com>, Jeff Moyer <jmoyer@...hat.com>,
	Jens Axboe <axboe@...com>, Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 12/39] block: Always check queue limits for cloned requests

From: Hannes Reinecke <hare@...e.de>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit bf4e6b4e757488dee1b6a581f49c7ac34cd217f8 upstream.

When a cloned request is retried on other queues it always needs
to be checked against the queue limits of that queue.
Otherwise the calculations for nr_phys_segments might be wrong,
leading to a crash in scsi_init_sgtable().

To clarify this the patch renames blk_rq_check_limits()
to blk_cloned_rq_check_limits() and removes the symbol
export, as the new function should only be used for
cloned requests and never exported.

Cc: Mike Snitzer <snitzer@...hat.com>
Cc: Ewan Milne <emilne@...hat.com>
Cc: Jeff Moyer <jmoyer@...hat.com>
Signed-off-by: Hannes Reinecke <hare@...e.de>
Fixes: e2a60da74 ("block: Clean up special command handling logic")
Acked-by: Mike Snitzer <snitzer@...hat.com>
Signed-off-by: Jens Axboe <axboe@...com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 block/blk-core.c       | 21 +++++++--------------
 include/linux/blkdev.h |  1 -
 2 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index bf214ae98937..de352508333f 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1893,7 +1893,8 @@ void submit_bio(int rw, struct bio *bio)
 EXPORT_SYMBOL(submit_bio);
 
 /**
- * blk_rq_check_limits - Helper function to check a request for the queue limit
+ * blk_cloned_rq_check_limits - Helper function to check a cloned request
+ *                              for new the queue limits
  * @q:  the queue
  * @rq: the request being checked
  *
@@ -1904,20 +1905,13 @@ EXPORT_SYMBOL(submit_bio);
  *    after it is inserted to @q, it should be checked against @q before
  *    the insertion using this generic function.
  *
- *    This function should also be useful for request stacking drivers
- *    in some cases below, so export this function.
  *    Request stacking drivers like request-based dm may change the queue
- *    limits while requests are in the queue (e.g. dm's table swapping).
- *    Such request stacking drivers should check those requests agaist
- *    the new queue limits again when they dispatch those requests,
- *    although such checkings are also done against the old queue limits
- *    when submitting requests.
+ *    limits when retrying requests on other queues. Those requests need
+ *    to be checked against the new queue limits again during dispatch.
  */
-int blk_rq_check_limits(struct request_queue *q, struct request *rq)
+static int blk_cloned_rq_check_limits(struct request_queue *q,
+				      struct request *rq)
 {
-	if (!rq_mergeable(rq))
-		return 0;
-
 	if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) {
 		printk(KERN_ERR "%s: over max size limit.\n", __func__);
 		return -EIO;
@@ -1937,7 +1931,6 @@ int blk_rq_check_limits(struct request_queue *q, struct request *rq)
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(blk_rq_check_limits);
 
 /**
  * blk_insert_cloned_request - Helper for stacking drivers to submit a request
@@ -1949,7 +1942,7 @@ int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
 	unsigned long flags;
 	int where = ELEVATOR_INSERT_BACK;
 
-	if (blk_rq_check_limits(q, rq))
+	if (blk_cloned_rq_check_limits(q, rq))
 		return -EIO;
 
 	if (rq->rq_disk &&
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b1056783c105..e66eba43d702 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -740,7 +740,6 @@ extern struct request *blk_make_request(struct request_queue *, struct bio *,
 extern void blk_requeue_request(struct request_queue *, struct request *);
 extern void blk_add_request_payload(struct request *rq, struct page *page,
 		unsigned int len);
-extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 extern int blk_lld_busy(struct request_queue *q);
 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 			     struct bio_set *bs, gfp_t gfp_mask,
-- 
2.7.0