[PATCH v4 1/3] mm/memory-failure: report MF_MSG_KERNEL for reserved pages

[Breno Leitao <leitao@debian.org>]

When get_hwpoison_page() returns a negative value, distinguish
reserved pages from other failure cases by reporting MF_MSG_KERNEL
instead of MF_MSG_GET_HWPOISON. Reserved pages belong to the kernel
and should be classified accordingly for proper handling.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 mm/memory-failure.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ee42d43613097..7b67e43dafbd1 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2432,7 +2432,16 @@ int memory_failure(unsigned long pfn, int flags)
 		}
 		goto unlock_mutex;
 	} else if (res < 0) {
-		res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED);
+		/*
+		 * PageReserved is stable here: reserved pages have
+		 * PG_reserved set at boot or by drivers and are never
+		 * freed through the page allocator.
+		 */
+		if (PageReserved(p))
+			res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED);
+		else
+			res = action_result(pfn, MF_MSG_GET_HWPOISON,
+					    MF_IGNORED);
 		goto unlock_mutex;
 	}
 

-- 
2.52.0