4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Junichi Nomura <j-nomura@xxxxxxxxxxxxx> commit f42d79ab67322e51b92dd7aa965e310c71352a64 upstream. tags is freed in blk_mq_free_rq_map() and should not be used after that. The problem doesn't manifest if CONFIG_CPUMASK_OFFSTACK is false because free_cpumask_var() is nop. tags->cpumask is allocated in blk_mq_init_tags() so it's natural to free cpumask in its counter part, blk_mq_free_tags(). Fixes: f26cdc8536ad ("blk-mq: Shared tag enhancements") Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx> Cc: Keith Busch <keith.busch@xxxxxxxxx> Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- block/blk-mq-tag.c | 1 + block/blk-mq.c | 4 +--- 2 files changed, 2 insertions(+), 3 deletions(-) --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -628,6 +628,7 @@ void blk_mq_free_tags(struct blk_mq_tags { bt_free(&tags->bitmap_tags); bt_free(&tags->breserved_tags); + free_cpumask_var(tags->cpumask); kfree(tags); } --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2263,10 +2263,8 @@ void blk_mq_free_tag_set(struct blk_mq_t int i; for (i = 0; i < set->nr_hw_queues; i++) { - if (set->tags[i]) { + if (set->tags[i]) blk_mq_free_rq_map(set, set->tags[i], i); - free_cpumask_var(set->tags[i]->cpumask); - } } kfree(set->tags); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html