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authorSukadev Bhattiprolu <[email protected]>2016-03-24 02:07:57 -0400
committerMichael Ellerman <[email protected]>2016-07-21 20:13:28 +1000
commit0eab46be21449f1612791201aa029facb676bd31 (patch)
treeec23ccf83fe827e4ec636293fab7ceaece0fadf4
parent31278b17a0dfed3014786b623fd07ee110b801da (diff)
powerpc/mm: Add memory barrier in __hugepte_alloc()
__hugepte_alloc() uses kmem_cache_zalloc() to allocate a zeroed PTE and proceeds to use the newly allocated PTE. Add a memory barrier to make sure that the other CPUs see a properly initialized PTE. Based on a fix suggested by James Dykman. Reported-by: James Dykman <[email protected]> Signed-off-by: Aneesh Kumar K.V <[email protected]> Signed-off-by: Sukadev Bhattiprolu <[email protected]> Tested-by: James Dykman <[email protected]> Signed-off-by: Michael Ellerman <[email protected]>
-rw-r--r--arch/powerpc/mm/hugetlbpage.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 5aac1a3f86cd..6be21e0f9095 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -81,6 +81,13 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
if (! new)
return -ENOMEM;
+ /*
+ * Make sure other cpus find the hugepd set only after a
+ * properly initialized page table is visible to them.
+ * For more details look for comment in __pte_alloc().
+ */
+ smp_wmb();
+
spin_lock(&mm->page_table_lock);
#ifdef CONFIG_PPC_FSL_BOOK3E
/*