+ mm-silence-data-race-in-update_hiwater_rss.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: silence data-race in update_hiwater_rss
has been added to the -mm mm-unstable branch.  Its filename is
     mm-silence-data-race-in-update_hiwater_rss.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-silence-data-race-in-update_hiwater_rss.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Lance Yang <lance.yang@linux.dev>
Subject: mm: silence data-race in update_hiwater_rss
Date: Fri, 26 Sep 2025 17:24:26 +0800

KCSAN reports a data race on mm_cluster.hiwater_rss, which can be accessed
concurrently from various paths like page migration and memory unmapping
without synchronization.

Since hiwater_rss is a statistical field for accounting purposes, this
data race is benign.  Annotate both the read and write accesses with
data_race() to make KCSAN happy.

Link: https://lkml.kernel.org/r/20250926092426.43312-1-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Reported-by: syzbot+60192c8877d0bc92a92b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/68d6364e.050a0220.3390a8.000d.GAE@google.com
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Marco Elver <elver@google.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mm.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/mm.h~mm-silence-data-race-in-update_hiwater_rss
+++ a/include/linux/mm.h
@@ -2742,7 +2742,7 @@ static inline void update_hiwater_rss(st
 	unsigned long _rss = get_mm_rss(mm);
 
 	if (data_race(mm->hiwater_rss) < _rss)
-		(mm)->hiwater_rss = _rss;
+		data_race(mm->hiwater_rss = _rss);
 }
 
 static inline void update_hiwater_vm(struct mm_struct *mm)
_

Patches currently in -mm which might be from lance.yang@linux.dev are

hung_task-fix-warnings-caused-by-unaligned-lock-pointers.patch
mm-thp-fix-mte-tag-mismatch-when-replacing-zero-filled-subpages.patch
mm-silence-data-race-in-update_hiwater_rss.patch
mm-clean-up-is_guard_pte_marker.patch