This is a note to let you know that I've just added the patch titled null_blk: Fix: memory release when memory_backed=1 to the 6.3-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: null_blk-fix-memory-release-when-memory_backed-1.patch and it can be found in the queue-6.3 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b2a9b2793036dd9e8b7e3dcb0d8d0ce014cb3f91 Author: Nitesh Shetty <nj.shetty@xxxxxxxxxxx> Date: Mon Jun 5 11:53:53 2023 +0530 null_blk: Fix: memory release when memory_backed=1 [ Upstream commit 8cfb98196cceec35416041c6b91212d2b99392e4 ] Memory/pages are not freed, when unloading nullblk driver. Steps to reproduce issue 1.free -h total used free shared buff/cache available Mem: 7.8Gi 260Mi 7.1Gi 3.0Mi 395Mi 7.3Gi Swap: 0B 0B 0B 2.modprobe null_blk memory_backed=1 3.dd if=/dev/urandom of=/dev/nullb0 oflag=direct bs=1M count=1000 4.modprobe -r null_blk 5.free -h total used free shared buff/cache available Mem: 7.8Gi 1.2Gi 6.1Gi 3.0Mi 398Mi 6.3Gi Swap: 0B 0B 0B Signed-off-by: Anuj Gupta <anuj20.g@xxxxxxxxxxx> Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20230605062354.24785-1-nj.shetty@xxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c index 14491952047f5..3b6b4cb400f42 100644 --- a/drivers/block/null_blk/main.c +++ b/drivers/block/null_blk/main.c @@ -2212,6 +2212,7 @@ static void null_destroy_dev(struct nullb *nullb) struct nullb_device *dev = nullb->dev; null_del_dev(nullb); + null_free_device_storage(dev, false); null_free_dev(dev); }