[merged mm-stable] mm-swapfile-mark-racy-access-on-si-highest_bit.patch removed from -mm tree

[merged mm-stable] mm-swapfile-mark-racy-access-on-si-highest_bit.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/swapfile: mark racy access on si->highest_bit
has been removed from the -mm tree.  Its filename was
     mm-swapfile-mark-racy-access-on-si-highest_bit.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: linke li <lilinke99@qq.com>
Subject: mm/swapfile: mark racy access on si->highest_bit
Date: Sat, 27 Apr 2024 14:29:56 +0800

In scan_swap_map_slots(), si->highest_bit can by changed by
swap_range_alloc() concurrently.  All reads on si->highest_bit except one
is either protected by lock or read using READ_ONCE.  So mark the one racy
read on si->highest_bit as benign using READ_ONCE.

This patch is aimed at reducing the number of benign races reported by
KCSAN in order to focus future debugging effort on harmful races.

Link: https://lkml.kernel.org/r/tencent_912BC3E8B0291DA4A0028AB424076375DA07@qq.com
Signed-off-by: linke li <lilinke99@qq.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- a/mm/swapfile.c~mm-swapfile-mark-racy-access-on-si-highest_bit
+++ a/mm/swapfile.c
@@ -902,7 +902,7 @@ static int scan_swap_map_slots(struct sw
 		last_in_cluster = offset + SWAPFILE_CLUSTER - 1;
 
 		/* Locate the first empty (unaligned) cluster */
-		for (; last_in_cluster <= si->highest_bit; offset++) {
+		for (; last_in_cluster <= READ_ONCE(si->highest_bit); offset++) {
 			if (si->swap_map[offset])
 				last_in_cluster = offset + SWAPFILE_CLUSTER;
 			else if (offset == last_in_cluster) {
_

Patches currently in -mm which might be from lilinke99@qq.com are