4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sagi Grimberg <sagi@xxxxxxxxxxx>
[ Upstream commit 0067d4b020ea07a58540acb2c5fcd3364bf326e0 ]
In case cpu was unplugged, we need to make sure not to assume
that the tags for that cpu are still allocated. so check
for null tags when reinitializing a tagset.
Reported-by: Yi Zhang <yizhan@xxxxxxxxxx>
Signed-off-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-mq-tag.c | 3 +++
1 file changed, 3 insertions(+)
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -311,6 +311,9 @@ int blk_mq_reinit_tagset(struct blk_mq_t
for (i = 0; i < set->nr_hw_queues; i++) {
struct blk_mq_tags *tags = set->tags[i];
+ if (!tags)
+ continue;
+
for (j = 0; j < tags->nr_tags; j++) {
if (!tags->rqs[j])
continue;