linux-kernel - [PATCH] mm/slub: mark racy access on slab->freelist

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Message-ID: <tencent_579220610AF1240FE3735A3443DBB01F9D07@qq.com>
Date: Sat, 27 Apr 2024 16:51:54 +0800
From: linke li <lilinke99@...com>
To: 
Cc: xujianhao01@...il.com,
	linke li <lilinke99@...com>,
	Christoph Lameter <cl@...ux.com>,
	Pekka Enberg <penberg@...nel.org>,
	David Rientjes <rientjes@...gle.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Vlastimil Babka <vbabka@...e.cz>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	Hyeonggon Yoo <42.hyeyoo@...il.com>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] mm/slub: mark racy access on slab->freelist

In deactivate_slab(), slab->freelist can be changed concurrently. Mark
data race on slab->freelist 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.

Signed-off-by: linke li <lilinke99@...com>
---
 mm/slub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index 0d700f6ca547..bb0e05a321e9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2813,7 +2813,7 @@ static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
 	struct slab new;
 	struct slab old;
 
-	if (slab->freelist) {
+	if (READ_ONCE(slab->freelist)) {
 		stat(s, DEACTIVATE_REMOTE_FREES);
 		tail = DEACTIVATE_TO_TAIL;
 	}
-- 
2.39.3 (Apple Git-146)