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authorJunichi Nomura <j-nomura@ce.jp.nec.com>2015-10-14 05:02:15 +0000
committerJens Axboe <axboe@fb.com>2015-10-15 08:45:58 -0600
commitf42d79ab67322e51b92dd7aa965e310c71352a64 (patch)
tree33b6533d2b7c96502f73d34910bb0f34ec4e0bd7 /block
parent835da3f99d329b1160a1f7fc82c7ac81163d63d0 (diff)
downloadlinux-f42d79ab67322e51b92dd7aa965e310c71352a64.tar.bz2
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>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq-tag.c1
-rw-r--r--block/blk-mq.c4
2 files changed, 2 insertions, 3 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index ed96474d75cb..ec2d11915142 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 7785ae96267a..85f014327342 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);