blk-mq: fix use-after-free in blk_mq_free_tag_set()
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>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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 @@
{
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 @@
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);