linux-kernel - [PATCH 2/4] mm: memory-failure: fix potential unexpected return value from unpoison

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Message-ID: <20230715031729.2420338-3-linmiaohe@huawei.com>
Date:   Sat, 15 Jul 2023 11:17:27 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>, <naoya.horiguchi@....com>
CC:     <shy828301@...il.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <linmiaohe@...wei.com>
Subject: [PATCH 2/4] mm: memory-failure: fix potential unexpected return value from unpoison_memory()

If unpoison_memory() fails to clear page hwpoisoned flag, return value
ret is expected to be -EBUSY. But when get_hwpoison_page() returns 1
and fails to clear page hwpoisoned flag due to races, return value will
be unexpected 1 leading to users being confused.

Fixes: bf181c582588 ("mm/hwpoison: fix unpoison_memory()")
Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/memory-failure.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 9ab97016877e..ac074f82f5b3 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2546,11 +2546,11 @@ int unpoison_memory(unsigned long pfn)
 			unpoison_pr_info("Unpoison: failed to grab page %#lx\n",
 					 pfn, &unpoison_rs);
 	} else {
+		ret = -EBUSY;
 		if (PageHuge(p)) {
 			huge = true;
 			count = folio_free_raw_hwp(folio, false);
 			if (count == 0) {
-				ret = -EBUSY;
 				folio_put(folio);
 				goto unlock_mutex;
 			}
-- 
2.33.0