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

blk_rq_map_user_iov: fix error override

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: blk_rq_map_user_iov-fix-error-override.patch and it can be found in the queue-4.9 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 69e0927b3774563c19b5fb32e91d75edc147fb62 Mon Sep 17 00:00:00 2001

From: Douglas Gilbert dgilbert@interlog.com Date: Sun, 14 Jan 2018 17:00:48 -0500 Subject: blk_rq_map_user_iov: fix error override

From: Douglas Gilbert dgilbert@interlog.com

commit 69e0927b3774563c19b5fb32e91d75edc147fb62 upstream.

During stress tests by syzkaller on the sg driver the block layer infrequently returns EINVAL. Closer inspection shows the block layer was trying to return ENOMEM (which is much more understandable) but for some reason overroad that useful error.

Patch below does not show this (unchanged) line: ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy); That 'ret' was being overridden when that function failed.

Signed-off-by: Douglas Gilbert dgilbert@interlog.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- block/blk-map.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/block/blk-map.c +++ b/block/blk-map.c @@ -116,7 +116,7 @@ int blk_rq_map_user_iov(struct request_q unsigned long align = q->dma_pad_mask | queue_dma_alignment(q); struct bio *bio = NULL; struct iov_iter i; - int ret; + int ret = -EINVAL;

if (!iter_is_iovec(iter)) goto fail; @@ -145,7 +145,7 @@ unmap_rq: __blk_rq_unmap_user(bio); fail: rq->bio = NULL; - return -EINVAL; + return ret; } EXPORT_SYMBOL(blk_rq_map_user_iov);

Patches currently in stable-queue which might be from dgilbert@interlog.com are

queue-4.9/blk_rq_map_user_iov-fix-error-override.patch