Messages in this thread Patch in this message | | | From | Junichi Nomura <> | Subject | [PATCH] blk-mq: fix use-after-free in blk_mq_free_tag_set() | Date | Wed, 14 Oct 2015 05:02:15 +0000 |
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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@ce.jp.nec.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Jens Axboe <axboe@fb.com> --- block/blk-mq-tag.c | 1 + block/blk-mq.c | 4 +--- 2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index ed96474..ec2d119 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -641,6 +641,7 @@ void blk_mq_free_tags(struct blk_mq_tags *tags) { bt_free(&tags->bitmap_tags); bt_free(&tags->breserved_tags); + free_cpumask_var(tags->cpumask); kfree(tags); } diff --git a/block/blk-mq.c b/block/blk-mq.c index 7785ae9..85f0143 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2296,10 +2296,8 @@ void blk_mq_free_tag_set(struct blk_mq_tag_set *set) 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); -- 2.1.0
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