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Date:   Tue, 8 Jun 2021 21:30:00 -0700 (PDT)
From:   Hugh Dickins <hughd@google.com>
To:     Andrew Morton <akpm@linux-foundation.org>
cc:     Hugh Dickins <hughd@google.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Yang Shi <shy828301@gmail.com>,
        Wang Yugui <wangyugui@e16-tech.com>,
        Matthew Wilcox <willy@infradead.org>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        Alistair Popple <apopple@nvidia.com>,
        Ralph Campbell <rcampbell@nvidia.com>, Zi Yan <ziy@nvidia.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Minchan Kim <minchan@kernel.org>, Jue Wang <juew@google.com>,
        Peter Xu <peterx@redhat.com>, Jan Kara <jack@suse.cz>,
        Shakeel Butt <shakeelb@google.com>,
        Oscar Salvador <osalvador@suse.de>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 10/10] mm: hwpoison_user_mappings() try_to_unmap() with
 TTU_SYNC
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TTU_SYNC prevents an unlikely race, when try_to_unmap() returns shortly
before the page is accounted as unmapped.  It is unlikely to coincide
with hwpoisoning, but now that we have the flag, hwpoison_user_mappings()
would do well to use it.

Signed-off-by: Hugh Dickins <hughd@google.com>
---
Patch added since the v1 series was posted.

 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 b6806e446567..e16edefca523 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1060,7 +1060,7 @@ static int get_hwpoison_page(struct page *p, unsigned long flags,
 static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 				  int flags, struct page **hpagep)
 {
-	enum ttu_flags ttu = TTU_IGNORE_MLOCK;
+	enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC;
 	struct address_space *mapping;
 	LIST_HEAD(tokill);
 	bool unmap_success;
-- 
2.26.2