summaryrefslogtreecommitdiff
path: root/block
diff options
context:
space:
mode:
authorBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>2016-05-16 09:54:47 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-05-10 10:26:24 +0200
commit655a064b05763765c583112110de7c621c3ee657 (patch)
treee37c01b953025ebb36a97245c666b1706061713d /block
parent6612b07fedc4273ef5dddc5ff066212db1ce74c1 (diff)
blk-mq: fix undefined behaviour in order_to_size()
commit b3a834b1596ac668df206aa2bb1f191c31f5f5e4 upstream. When this_order variable in blk_mq_init_rq_map() becomes zero the code incorrectly decrements the variable and passes the result to order_to_size() helper causing undefined behaviour: UBSAN: Undefined behaviour in block/blk-mq.c:1459:27 shift exponent 4294967295 is too large for 32-bit type 'unsigned int' CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.6.0-rc6-00072-g33656a1 #22 Fix the code by checking this_order variable for not having the zero value first. Reported-by: Meelis Roos <mroos@linux.ee> Fixes: 320ae51feed5 ("blk-mq: new multi-queue block IO queueing mechanism") Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8649dbf06ce4..b5633501f181 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1491,7 +1491,7 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
int to_do;
void *p;
- while (left < order_to_size(this_order - 1) && this_order)
+ while (this_order && left < order_to_size(this_order - 1))
this_order--;
do {