Commit 4e224719 authored by Christophe JAILLET's avatar Christophe JAILLET Committed by Greg Kroah-Hartman
Browse files

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.

Fixes: 4fb6eabf ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
Signed-off-by: default avatarChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3677563e

drivers/base/memory.c

+2 −3
Original line number Diff line number Diff line
@@ -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;

}