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Commit 4cb57ab4 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm bufio: initialize read-only module parameters 



Some module parameters in dm-bufio are read-only. These parameters
inform the user about memory consumption. They are not supposed to be
changed by the user.

However, despite being read-only, these parameters can be set on
modprobe or insmod command line, for example:
modprobe dm-bufio current_allocated_bytes=12345

The kernel doesn't expect that these variables can be non-zero at module
initialization and if the user sets them, it results in BUG.

This patch initializes the variables in the module init routine, so that
user-supplied values are ignored.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.2+
parent 08844800

drivers/md/dm-bufio.c

+5 −0
Original line number Diff line number Diff line
@@ -1717,6 +1717,11 @@ static int __init dm_bufio_init(void) 
{

	__u64 mem;



	dm_bufio_allocated_kmem_cache = 0;

	dm_bufio_allocated_get_free_pages = 0;

	dm_bufio_allocated_vmalloc = 0;

	dm_bufio_current_allocated = 0;



	memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches);

	memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names);