From f42d79ab67322e51b92dd7aa965e310c71352a64 Mon Sep 17 00:00:00 2001
From: Junichi Nomura
Date: Wed, 14 Oct 2015 05:02:15 +0000
Subject: 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>
---
 block/blk-mq-tag.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'block/blk-mq-tag.c')

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);
 }
 
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