From f47f758cff59c68015d6b9b9c077110df7c2c828 Mon Sep 17 00:00:00 2001 From: Christophe JAILLET Date: Thu, 28 Apr 2022 23:16:19 -0700 Subject: [PATCH] drivers/base/memory: fix an unlikely reference counting issue in __add_memory_block() __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@wanadoo.fr Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup") Signed-off-by: Christophe JAILLET Acked-by: Michal Hocko Reviewed-by: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Scott Cheloha Cc: Nathan Lynch Signed-off-by: Andrew Morton --- drivers/base/memory.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) 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; }