HWPOISON: fix invalid page count in printk output

The madvise injector already holds a reference when passing in a page
to the memory-failure code. The code corrects for this additional reference
for its checks, but the final printk output didn't. Fix that.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index e354b9f2f389..dacc64183874 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -613,13 +613,16 @@ static int page_action(struct page_state *ps, struct page *p,
                         unsigned long pfn, int ref)
 {
         int result;
+        int count;
 
         result = ps->action(p, pfn);
         action_result(pfn, ps->msg, result);
-        if (page_count(p) != 1 + ref)
+
+        count = page_count(p) - 1 - ref;
+        if (count != 0)
                 printk(KERN_ERR
                        "MCE %#lx: %s page still referenced by %d users\n",
-                       pfn, ps->msg, page_count(p) - 1);
+                       pfn, ps->msg, count);
 
         /* Could do more checks here if page looks ok */
         /*