This is a note to let you know that I've just added the patch titled drivers/base/memory: fix an unlikely reference counting issue in __add_memory_block() to the 5.18-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: drivers-base-memory-fix-an-unlikely-reference-counti.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 934833c4c985505c13922c192b73315e8065d2cb Author: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> Date: Thu Apr 28 23:16:19 2022 -0700 drivers/base/memory: fix an unlikely reference counting issue in __add_memory_block() [ Upstream commit f47f758cff59c68015d6b9b9c077110df7c2c828 ] __add_memory_block() calls both put_device() and device_unregister() when storing the memory block into the xarray. This is incorrect because xarray doesn't take an additional reference and device_unregister() already calls put_device(). Triggering the issue looks really unlikely and its only effect should be to log a spurious warning about a ref counted issue. Link: https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@xxxxxxxxxx Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup") Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> Cc: Scott Cheloha <cheloha@xxxxxxxxxxxxxxxxxx> Cc: Nathan Lynch <nathanl@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 7222ff9b5e05..084d67fd55cc 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -636,10 +636,9 @@ static int __add_memory_block(struct memory_block *memory) } ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory, GFP_KERNEL)); - if (ret) { - put_device(&memory->dev); + if (ret) device_unregister(&memory->dev); - } + return ret; }