aboutsummaryrefslogtreecommitdiff
path: root/block
diff options
context:
space:
mode:
authorMing Lei <ming.lei@canonical.com>2015-04-21 10:00:19 +0800
committerJens Axboe <axboe@fb.com>2015-04-23 10:27:35 -0600
commitf054b56c951bf1731ba7314a4c7f1cc0b2977cc9 (patch)
tree90cdfbaea772655ade496e030aae8c7c0a871945 /block
parent9283b42e46c2646dff1bec47e2dd683add7f9972 (diff)
downloadlinux-stericsson-f054b56c951bf1731ba7314a4c7f1cc0b2977cc9.tar.gz
blk-mq: fix race between timeout and CPU hotplug
Firstly during CPU hotplug, even queue is freezed, timeout handler still may come and access hctx->tags, which may cause use after free, so this patch deactivates timeout handler inside CPU hotplug notifier. Secondly, tags can be shared by more than one queues, so we have to check if the hctx has been unmapped, otherwise still use-after-free on tags can be triggered. Cc: <stable@vger.kernel.org> Reported-by: Dongsu Park <dongsu.park@profitbricks.com> Tested-by: Dongsu Park <dongsu.park@profitbricks.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ade8a2d1b0aa..1fccb98aa28f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -677,8 +677,11 @@ static void blk_mq_rq_timer(unsigned long priv)
data.next = blk_rq_timeout(round_jiffies_up(data.next));
mod_timer(&q->timeout, data.next);
} else {
- queue_for_each_hw_ctx(q, hctx, i)
- blk_mq_tag_idle(hctx);
+ queue_for_each_hw_ctx(q, hctx, i) {
+ /* the hctx may be unmapped, so check it here */
+ if (blk_mq_hw_queue_mapped(hctx))
+ blk_mq_tag_idle(hctx);
+ }
}
}
@@ -2090,9 +2093,16 @@ static int blk_mq_queue_reinit_notify(struct notifier_block *nb,
*/
list_for_each_entry(q, &all_q_list, all_q_node)
blk_mq_freeze_queue_start(q);
- list_for_each_entry(q, &all_q_list, all_q_node)
+ list_for_each_entry(q, &all_q_list, all_q_node) {
blk_mq_freeze_queue_wait(q);
+ /*
+ * timeout handler can't touch hw queue during the
+ * reinitialization
+ */
+ del_timer_sync(&q->timeout);
+ }
+
list_for_each_entry(q, &all_q_list, all_q_node)
blk_mq_queue_reinit(q);