[PATCH] nvme: fix use-after-free during booting

[Christoph Hellwig]

Hi Tong,

can you test this patch?

diff --git a/block/genhd.c b/block/genhd.c
index 99c64641c3148c..6473ae703789e4 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -836,6 +836,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 	 * so that it sticks around as long as @disk is there.
 	 */
 	WARN_ON_ONCE(!blk_get_queue(disk->queue));
+	disk->flags |= GENHD_FL_QUEUE_REF;
 
 	disk_add_events(disk);
 	blk_integrity_add(disk);
@@ -1567,7 +1568,7 @@ static void disk_release(struct device *dev)
 	kfree(disk->random);
 	disk_replace_part_tbl(disk, NULL);
 	hd_free_part(&disk->part0);
-	if (disk->queue)
+	if (disk->flags & GENHD_FL_QUEUE_REF)
 		blk_put_queue(disk->queue);
 	kfree(disk);
 }
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 4ab853461dff25..9441077ee10329 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -135,6 +135,7 @@ struct hd_struct {
 #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE	0x0100
 #define GENHD_FL_NO_PART_SCAN			0x0200
 #define GENHD_FL_HIDDEN				0x0400
+#define GENHD_FL_QUEUE_REF			0x0800
 
 enum {
 	DISK_EVENT_MEDIA_CHANGE			= 1 << 0, /* media changed */