[093/192] mm: hwpoison_user_mappings() try_to_unmap() with TTU_SYNC

Commit Message

Andrew Morton July 1, 2021, 1:52 a.m. UTC

From: Hugh Dickins <[e-mail]>
Subject: mm: hwpoison_user_mappings() try_to_unmap() with TTU_SYNC

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.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Hugh Dickins <[e-mail]>
Acked-by: Kirill A. Shutemov <[e-mail]>
Acked-by: Naoya Horiguchi <[e-mail]>
Cc: Alistair Popple <[e-mail]>
Cc: Jan Kara <[e-mail]>
Cc: Jue Wang <[e-mail]>
Cc: "Matthew Wilcox (Oracle)" <[e-mail]>
Cc: Miaohe Lin <[e-mail]>
Cc: Minchan Kim <[e-mail]>
Cc: Oscar Salvador <[e-mail]>
Cc: Peter Xu <[e-mail]>
Cc: Ralph Campbell <[e-mail]>
Cc: Shakeel Butt <[e-mail]>
Cc: Wang Yugui <[e-mail]>
Cc: Yang Shi <[e-mail]>
Cc: Zi Yan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/memory-failure.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

--- a/mm/memory-failure.c~mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync
+++ a/mm/memory-failure.c
@@ -1266,7 +1266,7 @@  static int get_hwpoison_page(struct page
 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;