path: root/mm
diff options
authorJoonsoo Kim <>2014-08-08 14:19:15 -0700
committerLinus Torvalds <>2014-08-08 15:57:17 -0700
commitedcad25095503c9a390bea0cc2f518793447a6a8 (patch)
treebc0512a4cc39ce7ec4a9a7b19f165edfcb786ad4 /mm
parent7f0d32e0c1a7a23216a0f2694ec841f60e9dddfd (diff)
Revert "slab: remove BAD_ALIEN_MAGIC"
This reverts commit a640616822b2 ("slab: remove BAD_ALIEN_MAGIC"). commit a640616822b2 ("slab: remove BAD_ALIEN_MAGIC") assumes that the system with !CONFIG_NUMA has only one memory node. But, it turns out to be false by the report from Geert. His system, m68k, has many memory nodes and is configured in !CONFIG_NUMA. So it couldn't boot with above change. Here goes his failure report. With latest mainline, I'm getting a crash during bootup on m68k/ARAnyM: enable_cpucache failed for radix_tree_node, error 12. kernel BUG at /scratch/geert/linux/linux-m68k/mm/slab.c:1522! *** TRAP #7 *** FORMAT=0 Current process id is 0 BAD KERNEL TRAP: 00000000 Modules linked in: PC: [<0039c92c>] kmem_cache_init_late+0x70/0x8c SR: 2200 SP: 00345f90 a2: 0034c2e8 d0: 0000003d d1: 00000000 d2: 00000000 d3: 003ac942 d4: 00000000 d5: 00000000 a0: 0034f686 a1: 0034f682 Process swapper (pid: 0, task=0034c2e8) Frame format=0 Stack from 00345fc4: 002f69ef 002ff7e5 000005f2 000360fa 0017d806 003921d4 00000000 00000000 00000000 00000000 00000000 00000000 003ac942 00000000 003912d6 Call Trace: [<000360fa>] parse_args+0x0/0x2ca [<0017d806>] strlen+0x0/0x1a [<003921d4>] start_kernel+0x23c/0x428 [<003912d6>] _sinittext+0x2d6/0x95e Code: f7e5 4879 002f 69ef 61ff ffca 462a 4e47 <4879> 0035 4b1c 61ff fff0 0cc4 7005 23c0 0037 fd20 588f 265f 285f 4e75 48e7 301c Disabling lock debugging due to kernel taint Kernel panic - not syncing: Attempted to kill the idle task! Although there is a alternative way to fix this issue such as disabling use of alien cache on !CONFIG_NUMA, but, reverting issued commit is better to me in this time. Signed-off-by: Joonsoo Kim <> Reported-by: Geert Uytterhoeven <> Cc: Christoph Lameter <> Cc: Pekka Enberg <> Cc: David Rientjes <> Cc: Vladimir Davydov <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'mm')
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 2e60bf3dedbb..a467b308c682 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -470,6 +470,8 @@ static struct kmem_cache kmem_cache_boot = {
.name = "kmem_cache",
+#define BAD_ALIEN_MAGIC 0x01020304ul
static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
@@ -836,7 +838,7 @@ static int transfer_objects(struct array_cache *to,
static inline struct alien_cache **alloc_alien_cache(int node,
int limit, gfp_t gfp)
- return NULL;
+ return (struct alien_cache **)BAD_ALIEN_MAGIC;
static inline void free_alien_cache(struct alien_cache **ac_ptr)