The patch titled
Subject: mm/slab: fix unaligned access on sparc64
has been added to the -mm tree. Its filename is
mm-slab-fix-unaligned-access-on-sparc64.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-slab-fix-unaligned-access-on-sparc64.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-slab-fix-unaligned-access-on-sparc64.patch
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From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: mm/slab: fix unaligned access on sparc64
commit bf0dea23a9c0 ("mm/slab: use percpu allocator for cpu cache")
changes allocation method for cpu cache array from slab allocator to
percpu allocator. Alignment should be provided for aligned memory in
percpu allocator case, but, that commit mistakenly set this alignment to
0. So, percpu allocator returns unaligned memory address. It doesn't
cause any problem on x86 which permits unaligned access, but, it causes
the problem on sparc64 which needs strong guarantee of alignment.
Following bug report is reported from David Miller.
I'm getting tons of the following on sparc64:
[603965.383447] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0
[603965.396987] Kernel unaligned access at TPC[546b60] free_block+0xa0/0x1a0
[603965.410523] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0
[603965.424061] Kernel unaligned access at TPC[546b60] free_block+0xa0/0x1a0
[603965.437617] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0
[603970.554394] log_unaligned: 333 callbacks suppressed
[603970.564041] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0
[603970.577576] Kernel unaligned access at TPC[546b60] free_block+0xa0/0x1a0
[603970.591122] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0
[603970.604669] Kernel unaligned access at TPC[546b60] free_block+0xa0/0x1a0
[603970.618216] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0
[603976.515633] log_unaligned: 31 callbacks suppressed
snip...
This patch provides proper alignment parameter when allocating cpu cache
to fix this unaligned memory access problem on sparc64.
Reported-by: David Miller <davem@xxxxxxxxxxxxx>
Tested-by: David Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/slab.c~mm-slab-fix-unaligned-access-on-sparc64 mm/slab.c
--- a/mm/slab.c~mm-slab-fix-unaligned-access-on-sparc64
+++ a/mm/slab.c
@@ -1992,7 +1992,7 @@ static struct array_cache __percpu *allo
struct array_cache __percpu *cpu_cache;
size = sizeof(void *) * entries + sizeof(struct array_cache);
- cpu_cache = __alloc_percpu(size, 0);
+ cpu_cache = __alloc_percpu(size, sizeof(void *));
if (!cpu_cache)
return NULL;
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
origin.patch
mm-slab-fix-unaligned-access-on-sparc64.patch
drivers-dma-coherent-add-initialization-from-device-tree.patch
drivers-dma-coherent-add-initialization-from-device-tree-fix.patch
drivers-dma-coherent-add-initialization-from-device-tree-fix-fix.patch
drivers-dma-coherent-add-initialization-from-device-tree-checkpatch-fixes.patch
drivers-dma-contiguous-add-initialization-from-device-tree.patch
page-owners-correct-page-order-when-to-free-page.patch
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