linux-kernel - [PATCH v1] mm: soft-offline: exit with failure for non anonymous thp

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Date:	Fri,  8 Jan 2016 16:24:02 +0900
From:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Naoya Horiguchi <nao.horiguchi@...il.com>
Subject: [PATCH v1] mm: soft-offline: exit with failure for non anonymous thp

Currently memory_failure() doesn't handle non anonymous thp case, because we
can hardly expect the error handling to be successful, and it can just hit
some corner case which results in BUG_ON or something severe like that.
This is also a case for soft offline code, so let's make it in the same way.

Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
---
 mm/memory-failure.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git v4.4-rc8/mm/memory-failure.c v4.4-rc8_patched/mm/memory-failure.c
index 750b789..30e9085 100644
--- v4.4-rc8/mm/memory-failure.c
+++ v4.4-rc8_patched/mm/memory-failure.c
@@ -1751,9 +1751,11 @@ int soft_offline_page(struct page *page, int flags)
 		return -EBUSY;
 	}
 	if (!PageHuge(page) && PageTransHuge(hpage)) {
-		if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
-			pr_info("soft offline: %#lx: failed to split THP\n",
-				pfn);
+		if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {
+			if (!PageAnon(hpage))
+				pr_info("soft offline: %#lx: non anonymous thp\n", pfn);
+			else
+				pr_info("soft offline: %#lx: thp split failed\n", pfn);
 			if (flags & MF_COUNT_INCREASED)
 				put_hwpoison_page(page);
 			return -EBUSY;
-- 
1.7.1