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authorWu Fengguang <fengguang.wu@intel.com>2009-12-16 12:19:57 +0100
committerAndi Kleen <ak@linux.intel.com>2009-12-16 12:19:57 +0100
commitbd1ce5f91f545730df4af492f774d9d32f5da3cb (patch)
tree7d25f35cda1f37e30fd21bb2375f2693837d5ec5 /mm/memory-failure.c
parenta7560fc80f33cab33176ee78f146df22b28e3338 (diff)
downloadlinux-bd1ce5f91f545730df4af492f774d9d32f5da3cb.tar.gz
HWPOISON: avoid grabbing the page count multiple times during madvise injection
If page is double referenced in madvise_hwpoison() and __memory_failure(),
remove_mapping() will fail because it expects page_count=2. Fix it by
not grabbing extra page count in __memory_failure().

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'mm/memory-failure.c')
-rw-r--r--mm/memory-failure.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 275f4e2df8ac..4253e14fa709 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -627,7 +627,7 @@ static void action_result(unsigned long pfn, char *msg, int result)
 }
 
 static int page_action(struct page_state *ps, struct page *p,
-			unsigned long pfn, int ref)
+			unsigned long pfn)
 {
 	int result;
 	int count;
@@ -635,7 +635,7 @@ static int page_action(struct page_state *ps, struct page *p,
 	result = ps->action(p, pfn);
 	action_result(pfn, ps->msg, result);
 
-	count = page_count(p) - 1 - ref;
+	count = page_count(p) - 1;
 	if (count != 0)
 		printk(KERN_ERR
 		       "MCE %#lx: %s page still referenced by %d users\n",
@@ -773,7 +773,7 @@ int __memory_failure(unsigned long pfn, int trapno, int ref)
 	 * In fact it's dangerous to directly bump up page count from 0,
 	 * that may make page_freeze_refs()/page_unfreeze_refs() mismatch.
 	 */
-	if (!get_page_unless_zero(compound_head(p))) {
+	if (!ref && !get_page_unless_zero(compound_head(p))) {
 		action_result(pfn, "free or high order kernel", IGNORED);
 		return PageBuddy(compound_head(p)) ? 0 : -EBUSY;
 	}
@@ -821,7 +821,7 @@ int __memory_failure(unsigned long pfn, int trapno, int ref)
 	res = -EBUSY;
 	for (ps = error_states;; ps++) {
 		if (((p->flags | lru_flag)& ps->mask) == ps->res) {
-			res = page_action(ps, p, pfn, ref);
+			res = page_action(ps, p, pfn);
 			break;
 		}
 	}