From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (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 D62635026C for ; Sun, 28 Apr 2024 08:10:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714291843; cv=none; b=cFlpBdDBFr0TNIav9fUVLu3OYV7K0yRfTthBXjVgtgsZT+X1U7xpyxQoB26m9oMp/+2+ikEbMqWDmzGtVYDNbEigOgntxmMseKNo9mjBkYMOhOJA+TrNHMo9a1gb4w7a7yZ87uxksYNE8Xy4MAAENr/EEaXKNm6rEyhedP0jUD8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714291843; c=relaxed/simple; bh=oP8HzgcB1FMYyJdJyci4YMdsOey+dfF/cOSQFEhy8L8=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=EEZaGk00S8K+XKHvf5Tx3+kFIKHSv7ASgDNlZbD3x/LGij/LeZzDeT04S3oKMKYythBPToxXHV089gI7UileqAqodsotyJneDqTMc71yDxDi8xTU9C8EnSZ9yOOd34BhI0H/DwUetLLAqmGnDENe6u/GPjyhrRO/pxgYW6J4+FU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=P08Xzlyl; arc=none smtp.client-ip=209.85.214.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="P08Xzlyl" Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-1eb1cb1a8f1so107365ad.0 for ; Sun, 28 Apr 2024 01:10:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1714291841; x=1714896641; darn=vger.kernel.org; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to; bh=Z3VQv9/zq8mi30peX/7MTevdNHF8DZN9NDCIotlMS04=; b=P08Xzlyl6z7dW0tLg/XK80F9WARPBB7miFv5KLhTQ0KwCLAJ7d7PmmR5IEAyPSBD8B WvKi56oLbMaeQpWE2xITEzcS44Z6w8mgDBuRKDcbgWRYyVGPdId/S88mxC8xLRBOwkpk VYsJ4VfTuhD4de7/r0LjVUx35rik+nRVxbM/1jDP/KOWlJdarL3kAcVrFzZnwIqFCC/F DZwz4Qr00zKJZrwe6h4PcqRrSPG3oEkPlRGQnKrRN90UGMKxv9niJN31/xUBr0WqrX38 /fCNsaJ5fHD5EBWzfICsAiEHNMwrVtAdafPrKmaJnAz3F6EM4FZ4Azj0WrdAHIU6U478 dOzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714291841; x=1714896641; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Z3VQv9/zq8mi30peX/7MTevdNHF8DZN9NDCIotlMS04=; b=Q5XLkdIfJ887OVlKUyvDFKLc7SddJ5d/4ZFlMRbbTEa0wqXC2cNWXbUCUu82bhNl7P GM4VDxwYe22trkNid/2cQvVHwL3wbsh7oqVM78rlRTkI6b6YQc8t3M8omUSxxXsAyrIQ cvfALqI3oeoVjo76hn+2cRYwb8t+j2q1bwvWH2N+CFfkc2rvGbefIBxyMibzCJlbnZrg 0op+wGz7r4iu6hjDZ383Ha8pJAfN1Xycv4Z6L9EpMfXZAzKCZ92V8KMntCP+gMOxzjVO KmwmoXkrOD/xeqmGDTxedBUFCSprVw/uyVE21iNOJt/7fEXae20AF3+WvN3qQAkh8JWO 4FcQ== X-Forwarded-Encrypted: i=1; AJvYcCVROsDNlNbNfGjIhe6FA6UR77KqXXwq62vFP56uMY6bCMPCveQTwc9wCBgnQzE4ETxmjSkcf/YluOpiRe4bHr6IWhX+lp9q7rMN0jg6 X-Gm-Message-State: AOJu0YyYW7L6SELj2F2QszATt5b2IvUq1EhkiY4Eg3Skmg9FEZjMGZTu E0+mWdI5ffcymvyVgY3g+EKKV67j97m5k8mRA+d6dPqXwHubw9LWtP50/qry3w== X-Google-Smtp-Source: AGHT+IEhYH7+1MRJ1fUfB80ujG9kMa1BLh5L7BL/3FgNdxfB0pfgNa40gnRtNf5ctZvpA4rVm+Zhrw== X-Received: by 2002:a17:902:d588:b0:1e4:35b9:cce0 with SMTP id k8-20020a170902d58800b001e435b9cce0mr157957plh.9.1714291840626; Sun, 28 Apr 2024 01:10:40 -0700 (PDT) Received: from [2620:0:1008:15:46db:4823:ceac:2ea3] ([2620:0:1008:15:46db:4823:ceac:2ea3]) by smtp.gmail.com with ESMTPSA id im15-20020a170902bb0f00b001e45572a253sm18481547plb.14.2024.04.28.01.10.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 28 Apr 2024 01:10:40 -0700 (PDT) Date: Sun, 28 Apr 2024 01:10:39 -0700 (PDT) From: David Rientjes To: linke li cc: xujianhao01@gmail.com, Christoph Lameter , Pekka Enberg , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slub: mark racy access on slab->freelist In-Reply-To: Message-ID: <1096134d-df6f-185d-240f-8a774d66f98f@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Sat, 27 Apr 2024, linke li wrote: > 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. > Thanks! Do you have a data race report to copy+paste into the commit description so people can search for it if they stumble across the same thing? > Signed-off-by: linke li > --- > 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) > >