The patch below does not apply to the 5.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8468f45091d2866affed6f6a7aecc20779139173 Mon Sep 17 00:00:00 2001

From: Coly Li colyli@suse.de Date: Wed, 3 Nov 2021 14:49:17 +0800 Subject: [PATCH] bcache: fix use-after-free problem in bcache_device_free()

In bcache_device_free(), pointer disk is referenced still in ida_simple_remove() after blk_cleanup_disk() gets called on this pointer. This may cause a potential panic by use-after-free on the disk pointer.

This patch fixes the problem by calling blk_cleanup_disk() after ida_simple_remove().

Fixes: bc70852fd104 ("bcache: convert to blk_alloc_disk/blk_cleanup_disk") Signed-off-by: Coly Li colyli@suse.de Cc: Christoph Hellwig hch@lst.de Cc: Hannes Reinecke hare@suse.de Cc: Ulf Hansson ulf.hansson@linaro.org Cc: stable@vger.kernel.org # v5.14+ Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20211103064917.67383-1-colyli@suse.de Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 84a48eed8e24..a7bb3355b776 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -885,9 +885,9 @@ static void bcache_device_free(struct bcache_device *d) bcache_device_detach(d);

if (disk) { - blk_cleanup_disk(disk); ida_simple_remove(&bcache_device_idx, first_minor_to_idx(disk->first_minor)); + blk_cleanup_disk(disk); }

bioset_exit(&d->bio_split);