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authorJens Axboe <axboe@fb.com>2016-08-02 08:45:44 -0600
committerJens Axboe <axboe@fb.com>2016-08-04 14:19:16 -0600
commitc0f3fd2b387448d67ae83c4ce1cc69da375b9186 (patch)
tree30fa18a04776d8735fd75d7c7adf9c4eb36d24bf /block
parent6d25ec147e3a71858bed5439c92accd7f739a0a3 (diff)
downloadlinux-stericsson-c0f3fd2b387448d67ae83c4ce1cc69da375b9186.tar.gz
blk-mq: fix deadlock in blk_mq_register_disk() error path
If we fail registering any of the hardware queues, we call into blk_mq_unregister_disk() with the hotplug mutex already held. Since blk_mq_unregister_disk() attempts to acquire the same mutex, we end up in a less than happy place. Reported-by: Jinpu Wang <jinpu.wang@profitbricks.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq-sysfs.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 4ea4dd8a1eed..fe822aa5b8e4 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -380,15 +380,13 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
return ret;
}
-void blk_mq_unregister_disk(struct gendisk *disk)
+static void __blk_mq_unregister_disk(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
struct blk_mq_hw_ctx *hctx;
struct blk_mq_ctx *ctx;
int i, j;
- blk_mq_disable_hotplug();
-
queue_for_each_hw_ctx(q, hctx, i) {
blk_mq_unregister_hctx(hctx);
@@ -405,6 +403,12 @@ void blk_mq_unregister_disk(struct gendisk *disk)
kobject_put(&disk_to_dev(disk)->kobj);
q->mq_sysfs_init_done = false;
+}
+
+void blk_mq_unregister_disk(struct gendisk *disk)
+{
+ blk_mq_disable_hotplug();
+ __blk_mq_unregister_disk(disk);
blk_mq_enable_hotplug();
}
@@ -450,7 +454,7 @@ int blk_mq_register_disk(struct gendisk *disk)
}
if (ret)
- blk_mq_unregister_disk(disk);
+ __blk_mq_unregister_disk(disk);
else
q->mq_sysfs_init_done = true;
out: