From: Christophe JAILLET christophe.jaillet@wanadoo.fr
[ 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/d44c63d78affe844f020dc02ad6af29abc448fc4.165061170... Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup") Signed-off-by: Christophe JAILLET christophe.jaillet@wanadoo.fr Acked-by: Michal Hocko mhocko@suse.com Reviewed-by: David Hildenbrand david@redhat.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: "Rafael J. Wysocki" rafael@kernel.org Cc: Scott Cheloha cheloha@linux.vnet.ibm.com Cc: Nathan Lynch nathanl@linux.ibm.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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; }