[PATCH 4/4] mm/memofy-failure.c: add hwpoison_filter for soft offline

[zhenwei pi]

hwpoison_filter is missing in the soft offline path, this leads an
issue: after enabling the corrupt filter, the user process still has
a chance to inject hwpoison fault by
madvise(addr, len, MADV_SOFT_OFFLINE) at PFN which is expected to
reject.

Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Signed-off-by: zhenwei pi <pizhenwei@xxxxxxxxxxxxx>
---
 mm/memory-failure.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index a6a27c8b800f..6564f5a34658 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2313,7 +2313,9 @@ static void put_ref_page(struct page *page)
  * @pfn: pfn to soft-offline
  * @flags: flags. Same as memory_failure().
  *
- * Returns 0 on success, otherwise negated errno.
+ * Returns 0 on success
+ *         -EOPNOTSUPP for memory_filter() filtered the error event
+ *         < 0 otherwise negated errno.
  *
  * Soft offline a page, by migration or invalidation,
  * without killing anything. This is for the case when
@@ -2350,6 +2352,11 @@ int soft_offline_page(unsigned long pfn, int flags)
 		return -EIO;
 	}
 
+	if (hwpoison_filter(page)) {
+		put_ref_page(ref_page);
+		return -EOPNOTSUPP;
+	}
+
 	mutex_lock(&mf_mutex);
 
 	if (PageHWPoison(page)) {
-- 
2.20.1