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>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 275f4e2..4253e14 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -627,7 +627,7 @@
}
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 @@
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 @@
* 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 @@
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;
}
}