diff options
authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2014-11-13 15:19:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-11-13 16:17:05 -0800
commit95069ac8da4975120ba76e968fc72948582c3509 (patch)
parent3c605096d3158216ba9326a16266f6ba128c2c8d (diff)
mm/slab: fix unalignment problem on Malta with EVA due to slab merge
Unlike SLUB, sometimes, object isn't started at the beginning of the slab in SLAB. This causes the unalignment problem after slab merging is supported by commit 12220dea07f1 ("mm/slab: support slab merge"). Following is the report from Markos that fail to boot on Malta with EVA. Calibrating delay loop... 19.86 BogoMIPS (lpj=99328) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 4096 (order: 0, 16384 bytes) Mountpoint-cache hash table entries: 4096 (order: 0, 16384 bytes) Kernel bug detected[#1]: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.17.0-05639-g12220dea07f1 #1631 task: 1f04f5d8 ti: 1f050000 task.ti: 1f050000 epc : 80141190 alloc_unbound_pwq+0x234/0x304 Not tainted ra : 80141184 alloc_unbound_pwq+0x228/0x304 Process swapper/0 (pid: 1, threadinfo=1f050000, task=1f04f5d8, tls=00000000) Call Trace: alloc_unbound_pwq+0x234/0x304 apply_workqueue_attrs+0x11c/0x294 __alloc_workqueue_key+0x23c/0x470 init_workqueues+0x320/0x400 do_one_initcall+0xe8/0x23c kernel_init_freeable+0x9c/0x224 kernel_init+0x10/0x100 ret_from_kernel_thread+0x14/0x1c [ end trace cb88537fdc8fa200 ] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b alloc_unbound_pwq() allocates slab object from pool_workqueue. This kmem_cache requires 256 bytes alignment, but, current merging code doesn't honor that, and merge it with kmalloc-256. kmalloc-256 requires only cacheline size alignment so that above failure occurs. However, in x86, kmalloc-256 is luckily aligned in 256 bytes, so the problem didn't happen on it. To fix this problem, this patch introduces alignment mismatch check in find_mergeable(). This will fix the problem. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reported-by: Markos Chandras <Markos.Chandras@imgtec.com> Tested-by: Markos Chandras <Markos.Chandras@imgtec.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 406944207b61..dcdab81bd240 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -259,6 +259,10 @@ struct kmem_cache *find_mergeable(size_t size, size_t align,
if (s->size - size >= sizeof(void *))
+ if (IS_ENABLED(CONFIG_SLAB) && align &&
+ (align > s->align || s->align % align))
+ continue;
return s;
return NULL;

Privacy Policy