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authorCatalin Marinas <catalin.marinas@arm.com>2020-07-02 12:19:30 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2020-09-04 14:46:06 +0300
commit72e6afa08e988744822f9bf18043fc04c4df2178 (patch)
tree2a93b64e0cb4c03c82bbb896215ff51151571f39 /mm/huge_memory.c
parent4beba9486abd2f86d125271d6946f7c38ed0fe77 (diff)
downloadlinux-72e6afa08e988744822f9bf18043fc04c4df2178.tar.xz
mm: Preserve the PG_arch_2 flag in __split_huge_page_tail()
When a huge page is split into normal pages, part of the head page flags are transferred to the tail pages. However, the PG_arch_* flags are not part of the preserved set. PG_arch_2 is used by the arm64 MTE support to mark pages that have valid tags. The absence of such flag would cause the arm64 set_pte_at() to clear the tags in order to avoid stale tags exposed to user or the swapping out hooks to ignore the tags. Not preserving PG_arch_2 on huge page splitting leads to tag corruption in the tail pages. Preserve the newly added PG_arch_2 flag in __split_huge_page_tail(). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2ccff8472cd4..1a5773c95f53 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2337,6 +2337,9 @@ static void __split_huge_page_tail(struct page *head, int tail,
(1L << PG_workingset) |
(1L << PG_locked) |
(1L << PG_unevictable) |
+#ifdef CONFIG_64BIT
+ (1L << PG_arch_2) |
+#endif
(1L << PG_dirty)));
/* ->mapping in first tail page is compound_mapcount */