cfq_get_queue: fix possible NULL pointer access
cfq_get_queue()->cfq_find_alloc_queue() can fail, check the returned value.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Note that this isn't a bug at the moment, since the regular IO path
does not call this path without __GFP_WAIT set. However, it could be a
future bug, so I've applied it.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index d77c971..e47a930 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1443,8 +1443,11 @@
cfqq = *async_cfqq;
}
- if (!cfqq)
+ if (!cfqq) {
cfqq = cfq_find_alloc_queue(cfqd, is_sync, tsk, gfp_mask);
+ if (!cfqq)
+ return NULL;
+ }
/*
* pin the queue now that it's allocated, scheduler exit will prune it