diff options
authorAdam Litke <>2006-08-18 11:22:21 -0700
committerPaul Mackerras <>2006-08-24 10:07:23 +1000
commitc9169f8747bb282cbe518132bf7d49755a00b6c1 (patch)
parentd55c4a76f26160482158cd43788dcfc96a320a4f (diff)
[POWERPC] hugepage BUG fix
On Tue, 2006-08-15 at 08:22 -0700, Dave Hansen wrote: > kernel BUG in cache_free_debugcheck at mm/slab.c:2748! Alright, this one is only triggered when slab debugging is enabled. The slabs are assumed to be aligned on a HUGEPTE_TABLE_SIZE boundary. The free path makes use of this assumption and uses the lowest nibble to pass around an index into an array of kmem_cache pointers. With slab debugging turned on, the slab is still aligned, but the "working" object pointer is not. This would break the assumption above that a full nibble is available for the PGF_CACHENUM_MASK. The following patch reduces PGF_CACHENUM_MASK to cover only the two least significant bits, which is enough to cover the current number of 4 pgtable cache types. Then use this constant to mask out the appropriate part of the huge pte pointer. Signed-off-by: Adam Litke <> Signed-off-by: Andrew Morton <> Signed-off-by: Paul Mackerras <>
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 266b8b2ceac9..5615acc29527 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -153,7 +153,7 @@ static void free_hugepte_range(struct mmu_gather *tlb, hugepd_t *hpdp)
hpdp->pd = 0;
tlb->need_flush = 1;
pgtable_free_tlb(tlb, pgtable_free_cache(hugepte, HUGEPTE_CACHE_NUM,
diff --git a/include/asm-powerpc/pgalloc.h b/include/asm-powerpc/pgalloc.h
index 9f0917c68659..ae63db7b3e7d 100644
--- a/include/asm-powerpc/pgalloc.h
+++ b/include/asm-powerpc/pgalloc.h
@@ -117,7 +117,7 @@ static inline void pte_free(struct page *ptepage)
-#define PGF_CACHENUM_MASK 0xf
+#define PGF_CACHENUM_MASK 0x3
typedef struct pgtable_free {
unsigned long val;