mm: hwpoison: call shake_page() unconditionally

shake_page() is called before going into core error handling code in
order to ensure that the error page is flushed from lru_cache lists
where pages stay during transferring among LRU lists.

But currently it's not fully functional because when the page is linked
to lru_cache by calling activate_page(), its PageLRU flag is set and
shake_page() is skipped.  The result is to fail error handling with
"still referenced by 1 users" message.

When the page is linked to lru_cache by isolate_lru_page(), its PageLRU
is clear, so that's fine.

This patch makes shake_page() unconditionally called to avoild the
failure.

Fixes: 23a003bfd23ea9ea0b7756b920e51f64b284b468 ("mm/madvise: pass return code of memory_failure() to userspace")
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Link: http://lkml.kernel.org/r/1493197841-23986-2-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Xiaolong Ye <xiaolong.ye@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 12 insertions, 18 deletions

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index 9d26fd9fefe4..356df057a2a8 100644
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -34,8 +34,7 @@ static int hwpoison_inject(void *data, u64 val)
         if (!hwpoison_filter_enable)
                 goto inject;
 
-        if (!PageLRU(hpage) && !PageHuge(p))
-                shake_page(hpage, 0);
+        shake_page(hpage, 0);
         /*
          * This implies unable to support non-LRU pages.
          */
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 92865bb1816d..9d87fcab96c9 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -220,6 +220,9 @@ static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
  */
 void shake_page(struct page *p, int access)
 {
+        if (PageHuge(p))
+                return;
+
         if (!PageSlab(p)) {
                 lru_add_drain_all();
                 if (PageLRU(p))
@@ -1137,22 +1140,14 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
          * The check (unnecessarily) ignores LRU pages being isolated and
          * walked by the page reclaim code, however that's not a big loss.
          */
-        if (!PageHuge(p)) {
-                if (!PageLRU(p))
-                        shake_page(p, 0);
-                if (!PageLRU(p)) {
-                        /*
-                         * shake_page could have turned it free.
-                         */
-                        if (is_free_buddy_page(p)) {
-                                if (flags & MF_COUNT_INCREASED)
-                                        action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
-                                else
-                                        action_result(pfn, MF_MSG_BUDDY_2ND,
-                                                      MF_DELAYED);
-                                return 0;
-                        }
-                }
+        shake_page(p, 0);
+        /* shake_page could have turned it free. */
+        if (!PageLRU(p) && is_free_buddy_page(p)) {
+                if (flags & MF_COUNT_INCREASED)
+                        action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
+                else
+                        action_result(pfn, MF_MSG_BUDDY_2ND, MF_DELAYED);
+                return 0;
         }
 
         lock_page(hpage);