Re: unaligned accesses in SLAB etc.

[Joonsoo Kim <js1304@xxxxxxxxx>]

2014-10-12 11:15 GMT+09:00 David Miller <davem@xxxxxxxxxxxxx>:
>
> 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
> [603976.525092] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603976.540196] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603976.555308] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603976.570411] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603976.585526] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603982.476424] log_unaligned: 43 callbacks suppressed
> [603982.485881] Kernel unaligned access at TPC[549378] kmem_cache_alloc+0xd8/0x1e0
> [603982.501590] Kernel unaligned access at TPC[5470a8] kmem_cache_free+0xc8/0x200
> [603982.501605] Kernel unaligned access at TPC[549378] kmem_cache_alloc+0xd8/0x1e0
> [603982.530382] Kernel unaligned access at TPC[5470a8] kmem_cache_free+0xc8/0x200
> [603982.544820] Kernel unaligned access at TPC[549378] kmem_cache_alloc+0xd8/0x1e0
> [603987.567130] log_unaligned: 11 callbacks suppressed
> [603987.576582] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603987.591696] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603987.606811] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603987.621904] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0
> [603987.637017] Kernel unaligned access at TPC[548080] cache_alloc_refill+0x180/0x3a0

Hello,

Could you test below patch?
If it fixes your problem, I will send it with proper description.

Thanks.

---------->8----------------
diff --git a/mm/slab.c b/mm/slab.c
index 154aac8..eb2b2ea 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1992,7 +1992,7 @@ static struct array_cache __percpu *alloc_kmem_cache_cpus(
        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;

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