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

[Christoph Hellwig]

I suspect the patch below might be better.  Can you send me a full dmesg
with this one applied?  Preferably on top of Jens' for-next branch?


diff --git a/block/genhd.c b/block/genhd.c
index 9d060e79eb31d8..ef2784c69d59ee 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -832,7 +832,9 @@ static void __device_add_disk(struct device *parent, struct 
gendisk *disk,
         * Take an extra ref on queue which will be put on disk_release()
         * so that it sticks around as long as @disk is there.
         */
-       WARN_ON_ONCE(!blk_get_queue(disk->queue));
+       WARN_ON_ONCE(blk_queue_dying(disk->queue));
+       __blk_get_queue(disk->queue);
+       disk->flags |= GENHD_FL_QUEUE_REF;
 
        disk_add_events(disk);
        blk_integrity_add(disk);
@@ -1564,7 +1566,7 @@ 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 1c97cf84f011a7..822a619924e3b5 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -133,6 +133,7 @@ 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 */