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authorHugh Dickins <hughd@google.com>2012-02-08 17:13:40 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-02-13 11:06:11 -0800
commit91b08ca08c8f5fbad289950086d6fb7ab0642d63 (patch)
treea9229fcb99dd4f846ca1577c213d822345f52a28 /mm/huge_memory.c
parentb9134812300fd0e3c242c50af5c563065d2f1b1e (diff)
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mm: fix UP THP spin_is_locked BUGs
commit b9980cdcf2524c5fe15d8cbae9c97b3ed6385563 upstream. Fix CONFIG_TRANSPARENT_HUGEPAGE=y CONFIG_SMP=n CONFIG_DEBUG_VM=y CONFIG_DEBUG_SPINLOCK=n kernel: spin_is_locked() is then always false, and so triggers some BUGs in Transparent HugePage codepaths. asm-generic/bug.h mentions this problem, and provides a WARN_ON_SMP(x); but being too lazy to add VM_BUG_ON_SMP, BUG_ON_SMP, WARN_ON_SMP_ONCE, VM_WARN_ON_SMP_ONCE, just test NR_CPUS != 1 in the existing VM_BUG_ONs. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index cc5acf9..78a83e7 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2020,7 +2020,7 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
{
struct mm_struct *mm = mm_slot->mm;
- VM_BUG_ON(!spin_is_locked(&khugepaged_mm_lock));
+ VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
if (khugepaged_test_exit(mm)) {
/* free mm_slot */
@@ -2048,7 +2048,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
int progress = 0;
VM_BUG_ON(!pages);
- VM_BUG_ON(!spin_is_locked(&khugepaged_mm_lock));
+ VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
if (khugepaged_scan.mm_slot)
mm_slot = khugepaged_scan.mm_slot;