From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2ABDC43331 for ; Tue, 31 Mar 2020 11:39:49 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 301C720838 for ; Tue, 31 Mar 2020 11:39:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="U5XF6eyg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 301C720838 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-18329-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 5304 invoked by uid 550); 31 Mar 2020 11:39:28 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 7466 invoked from network); 30 Mar 2020 23:20:03 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585610391; bh=knMGEU53xC+KPtKJP1jsuRoJ7sa4gkeHaJVEPUc4f7Y=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=U5XF6eygiF8K/M6F+FMs3jEOjwHcIgGS9MuHISkDZX3KyqITcsD8Xs1yD+UVKVXGM tHl5zq4QhbfFv04/h+wmlll0DUgUESlTLoM1jqIkVs9LBv9cVPtQVTw1oM7Js11ZuJ zKnLUqTXu2m7dAXVATi7QmOizyd+rO8Af/b1+3P0= Date: Mon, 30 Mar 2020 16:19:51 -0700 From: "Paul E. McKenney" To: Will Deacon Cc: linux-kernel@vger.kernel.org, Eric Dumazet , Jann Horn , Kees Cook , Maddie Stone , Marco Elver , Peter Zijlstra , Thomas Gleixner , kernel-team@android.com, kernel-hardening@lists.openwall.com Subject: Re: [RFC PATCH 07/21] Revert "list: Use WRITE_ONCE() when adding to lists and hlists" Message-ID: <20200330231951.GB19865@paulmck-ThinkPad-P72> References: <20200324153643.15527-1-will@kernel.org> <20200324153643.15527-8-will@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200324153643.15527-8-will@kernel.org> User-Agent: Mutt/1.9.4 (2018-02-28) On Tue, Mar 24, 2020 at 03:36:29PM +0000, Will Deacon wrote: > This reverts commit 1c97be677f72b3c338312aecd36d8fff20322f32. > > There is no need to use WRITE_ONCE() for the non-RCU list and hlist > implementations. > > Cc: Paul E. McKenney > Cc: Peter Zijlstra > Signed-off-by: Will Deacon Which means that the lockless uses of hlist_empty() will also need attention, correct? Thanx, Paul > --- > include/linux/list.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/include/linux/list.h b/include/linux/list.h > index ec1f780d1449..c7331c259792 100644 > --- a/include/linux/list.h > +++ b/include/linux/list.h > @@ -70,7 +70,7 @@ static inline void __list_add(struct list_head *new, > next->prev = new; > new->next = next; > new->prev = prev; > - WRITE_ONCE(prev->next, new); > + prev->next = new; > } > > /** > @@ -843,7 +843,7 @@ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) > n->next = first; > if (first) > first->pprev = &n->next; > - WRITE_ONCE(h->first, n); > + h->first = n; > n->pprev = &h->first; > } > > @@ -858,7 +858,7 @@ static inline void hlist_add_before(struct hlist_node *n, > n->pprev = next->pprev; > n->next = next; > next->pprev = &n->next; > - WRITE_ONCE(*(n->pprev), n); > + *(n->pprev) = n; > } > > /** > -- > 2.20.1 >