[PATCH AUTOSEL 5.2 14/63] rbd: fix response length parameter for encoded strings

[PATCH AUTOSEL 5.2 14/63] rbd: fix response length parameter for encoded strings

[Sasha Levin]

From: Dongsheng Yang <dongsheng.yang@easystack.cn>

[ Upstream commit 5435d2069503e2aa89c34a94154f4f2fa4a0c9c4 ]

rbd_dev_image_id() allocates space for length but passes a smaller
value to rbd_obj_method_sync().  rbd_dev_v2_object_prefix() doesn't
allocate space for length.  Fix both to be consistent.

Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/block/rbd.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index e5009a34f9c26..e78794bfcbbef 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4696,17 +4696,20 @@ static int rbd_dev_v2_image_size(struct rbd_device *rbd_dev)
 
 static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)
 {
+	size_t size;
 	void *reply_buf;
 	int ret;
 	void *p;
 
-	reply_buf = kzalloc(RBD_OBJ_PREFIX_LEN_MAX, GFP_KERNEL);
+	/* Response will be an encoded string, which includes a length */
+	size = sizeof(__le32) + RBD_OBJ_PREFIX_LEN_MAX;
+	reply_buf = kzalloc(size, GFP_KERNEL);
 	if (!reply_buf)
 		return -ENOMEM;
 
 	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
 				  &rbd_dev->header_oloc, "get_object_prefix",
-				  NULL, 0, reply_buf, RBD_OBJ_PREFIX_LEN_MAX);
+				  NULL, 0, reply_buf, size);
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret < 0)
 		goto out;
@@ -5676,7 +5679,6 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
 	dout("rbd id object name is %s\n", oid.name);
 
 	/* Response will be an encoded string, which includes a length */
-
 	size = sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX;
 	response = kzalloc(size, GFP_NOIO);
 	if (!response) {
@@ -5688,7 +5690,7 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
 
 	ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
 				  "get_id", NULL, 0,
-				  response, RBD_IMAGE_ID_LEN_MAX);
+				  response, size);
 	dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
 	if (ret == -ENOENT) {
 		image_id = kstrdup("", GFP_KERNEL);
-- 
2.20.1

[PATCH AUTOSEL 5.2 48/63] blk-mq: move lockdep_assert_held() into elevator_exit

[Sasha Levin]

From: Ming Lei <ming.lei@redhat.com>

[ Upstream commit 284b94be1925dbe035ce5218d8b5c197321262c7 ]

Commit c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq")
removes q->sysfs_lock from elevator_init_mq(), but forgot to deal with
lockdep_assert_held() called in blk_mq_sched_free_requests() which is
run in failure path of elevator_init_mq().

blk_mq_sched_free_requests() is called in the following 3 functions:

	elevator_init_mq()
	elevator_exit()
	blk_cleanup_queue()

In blk_cleanup_queue(), blk_mq_sched_free_requests() is followed exactly
by 'mutex_lock(&q->sysfs_lock)'.

So moving the lockdep_assert_held() from blk_mq_sched_free_requests()
into elevator_exit() for fixing the report by syzbot.

Reported-by: syzbot+da3b7677bb913dc1b737@syzkaller.appspotmail.com
Fixed: c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 block/blk-mq-sched.c | 2 --
 block/blk.h          | 2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 2766066a15dbf..3cf555f127006 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -554,8 +554,6 @@ void blk_mq_sched_free_requests(struct request_queue *q)
 	struct blk_mq_hw_ctx *hctx;
 	int i;
 
-	lockdep_assert_held(&q->sysfs_lock);
-
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (hctx->sched_tags)
 			blk_mq_free_rqs(q->tag_set, hctx->sched_tags, i);
diff --git a/block/blk.h b/block/blk.h
index 7814aa207153c..38938125ab729 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -184,6 +184,8 @@ void elv_unregister_queue(struct request_queue *q);
 static inline void elevator_exit(struct request_queue *q,
 		struct elevator_queue *e)
 {
+	lockdep_assert_held(&q->sysfs_lock);
+
 	blk_mq_sched_free_requests(q);
 	__elevator_exit(q, e);
 }
-- 
2.20.1