From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f54.google.com (mail-wm1-f54.google.com [209.85.128.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19D6413FEE for ; Fri, 26 Sep 2025 09:24:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758878693; cv=none; b=lTGivvYZ7L7VSTbVCHdvKmbTOpf7u1jWdlGwW1eMz0GP9A7RNkFLUJvRl2IfXQHm5uTUjgbzUpuVsAnD8mKcX64CbCedrTPeZp7TQLWaSAmjgzPuxv7UlFFsuYT97t3giFUsbVixsQ6ZoNyMul0vJnhz8Y+o/Tfw4piNjlQFIVo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758878693; c=relaxed/simple; bh=swfP+KXfulFeSbvNBtN3sK+wM+xnt2dlSOlEHsnQmDE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=aVQr+UAOY0mHjwT1wcG0c9B4lYKSPPyY8n5I5gHPU244AK68HCPH+lgoZj+rm/iI1JcncAuPJeLMzw5WVpus27tLlWwsRGFUeJbWxSBEvm/4MvHpxUXo+5hTHSV5cI5Or83ktnDoxZbxbWQNHyApmhuEqrWDKNMRvhctBU3ir9w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.128.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-wm1-f54.google.com with SMTP id 5b1f17b1804b1-46e2e6a708fso11199455e9.0 for ; Fri, 26 Sep 2025 02:24:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758878690; x=1759483490; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=15qqzO1/4D/fXvObyf6lxUzcRGeGiwoHvTPaLubu2a8=; b=TMHIJ8ZjlciritAJQH9GQmkT9rA4D4KHyM75ESbccv35H05uczCJFFGEiVbTm8G/KM Cg5TlOO8i3PTXd1wGb64bZM/c2sML2dKeI+LMFgUFHoKYPJW01dPkCSm7XcBktbrihXm VZoqKakw90q5docUV3BxnDMC2G3XPSDAcx1MlZHhmtd1pRmNznKoPaZMmJbno0Epf0KY L/zBcgS4lcr+tMphfHJR6+si8cel+T+O08u+Xy4xmtJMf/tWCcrOMhy40lJ8Fyvl7LQL R5uWLG8/aV3L/dxOBEr9kftkutg0WgwofNNyFBSy4wbW/NzsSB6LC5Zze0QucW7GCvOz blgA== X-Forwarded-Encrypted: i=1; AJvYcCVY2FPsfUUr1vccsqnaepwm8t8AsAxKkivRSisFSA8BCAOsssbAiAXdG5GHfI+kAPcZywNBWUOdXqqY1zs=@vger.kernel.org X-Gm-Message-State: AOJu0YzSt2pszk1y7ipFENkUMvIzcrStVSFeE/NthibtgGefTvsAePFJ EI6F+qfSHAizViqxBkvaJSN4f4Zyi1p1VzWTisVg4gaP/NoqKaE1AkAp X-Gm-Gg: ASbGncv4F6jjpo6JAO1BteCZMg/r2I1xfmTd5WfJ5g3X77veqdnPE1gRTwPD7IH1etR sWmBGcg2up2Wl9sertfvea5IcS6YUPpVF6Dd+fgHH1fycs3haTZDJo1azCjIVAuYdmWGBD3jAsk TbxoFetPuiex4aus8uLLI8PYDfmr+S0UM2Q4YiwWmEE6KRMRRmJ2E17IPADsRNeSES0qg6NLc/5 97xFJQAL24+zdwF/hXQcCBFm0gvTuPjWCIIxd9VSBlPhd7AT/UnmDiRRJypTw2tyDA9nEqf4OCI pBtiIALq9oZeAEQzeLCQmSHXHZqBwqIc1H54P0BeMKkLGNw4mvYYLri0RBTLtQH9p0gX8eBS9M5 MFvPo5MJ3RaD1YcYNYpC0Zt0= X-Google-Smtp-Source: AGHT+IG4jF+clSglFjlTRLQXXovvviBd+u8T240DwlX27xdVKmc4bcBJNd8Gdkqs1y2zUe90wtCrSg== X-Received: by 2002:a05:600c:5491:b0:46e:345d:dfde with SMTP id 5b1f17b1804b1-46e345de049mr68882005e9.16.1758878690199; Fri, 26 Sep 2025 02:24:50 -0700 (PDT) Received: from EBJ9932692.tcent.cn ([2a09:0:1:2::3086]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46e2ab48b40sm108503725e9.19.2025.09.26.02.24.45 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 26 Sep 2025 02:24:49 -0700 (PDT) From: Lance Yang To: akpm@linux-foundation.org Cc: elver@google.com, Liam.Howlett@oracle.com, david@redhat.com, harry.yoo@oracle.com, jannh@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, riel@surriel.com, syzkaller-bugs@googlegroups.com, vbabka@suse.cz, syzbot+60192c8877d0bc92a92b@syzkaller.appspotmail.com, Lance Yang Subject: [PATCH 1/1] mm: silence data-race in update_hiwater_rss Date: Fri, 26 Sep 2025 17:24:26 +0800 Message-ID: <20250926092426.43312-1-lance.yang@linux.dev> X-Mailer: git-send-email 2.49.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Lance Yang 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. Reported-by: syzbot+60192c8877d0bc92a92b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-mm/68d6364e.050a0220.3390a8.000d.GAE@google.com Signed-off-by: Lance Yang --- include/linux/mm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 6b6c6980f46c..dd93335e3a13 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2757,7 +2757,7 @@ static inline void update_hiwater_rss(struct mm_struct *mm) 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) -- 2.49.0