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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65E6CC83F16 for ; Mon, 28 Aug 2023 10:41:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231684AbjH1KlB (ORCPT ); Mon, 28 Aug 2023 06:41:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231720AbjH1Kkf (ORCPT ); Mon, 28 Aug 2023 06:40:35 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37383B9 for ; Mon, 28 Aug 2023 03:40:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C97A464070 for ; Mon, 28 Aug 2023 10:40:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC2AFC433C8; Mon, 28 Aug 2023 10:40:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1693219232; bh=tj4ELLTSTvw7I3Wr9SXE9S7MyEWCdLsfBmDmQ5uBnD8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AUbuiIddc7bDrGoGqCuspKc4f4X5oHbZ/OTqx1NnHTf3fiCojM6B60fh8a+bsISe6 k20nN+/y2+Kpe29XJM2s0KfU5Ft1sgp59eoDGtwJ/DUcTGIZox3fM4+otzJMt9W/V8 afsu36xxOCkoTl/WU1IOiXi9EzFHR0s+thTVAz3s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Abel Wu , Shakeel Butt , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 120/158] sock: annotate data-races around prot->memory_pressure Date: Mon, 28 Aug 2023 12:13:37 +0200 Message-ID: <20230828101201.389613488@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230828101157.322319621@linuxfoundation.org> References: <20230828101157.322319621@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 76f33296d2e09f63118db78125c95ef56df438e9 ] *prot->memory_pressure is read/writen locklessly, we need to add proper annotations. A recent commit added a new race, it is time to audit all accesses. Fixes: 2d0c88e84e48 ("sock: Fix misuse of sk_under_memory_pressure()") Fixes: 4d93df0abd50 ("[SCTP]: Rewrite of sctp buffer management code") Signed-off-by: Eric Dumazet Cc: Abel Wu Reviewed-by: Shakeel Butt Link: https://lore.kernel.org/r/20230818015132.2699348-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/sock.h | 7 ++++--- net/sctp/socket.c | 2 +- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index 61f5872aac24f..f73ef7087a187 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1161,6 +1161,7 @@ struct proto { /* * Pressure flag: try to collapse. * Technical note: it is used by multiple contexts non atomically. + * Make sure to use READ_ONCE()/WRITE_ONCE() for all reads/writes. * All the __sk_mem_schedule() is of this nature: accounting * is strict, actions are advisory and have some latency. */ @@ -1277,7 +1278,7 @@ static inline bool sk_has_memory_pressure(const struct sock *sk) static inline bool sk_under_global_memory_pressure(const struct sock *sk) { return sk->sk_prot->memory_pressure && - !!*sk->sk_prot->memory_pressure; + !!READ_ONCE(*sk->sk_prot->memory_pressure); } static inline bool sk_under_memory_pressure(const struct sock *sk) @@ -1289,7 +1290,7 @@ static inline bool sk_under_memory_pressure(const struct sock *sk) mem_cgroup_under_socket_pressure(sk->sk_memcg)) return true; - return !!*sk->sk_prot->memory_pressure; + return !!READ_ONCE(*sk->sk_prot->memory_pressure); } static inline long @@ -1343,7 +1344,7 @@ proto_memory_pressure(struct proto *prot) { if (!prot->memory_pressure) return false; - return !!*prot->memory_pressure; + return !!READ_ONCE(*prot->memory_pressure); } diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 7cff1a031f761..431b9399a781f 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -97,7 +97,7 @@ struct percpu_counter sctp_sockets_allocated; static void sctp_enter_memory_pressure(struct sock *sk) { - sctp_memory_pressure = 1; + WRITE_ONCE(sctp_memory_pressure, 1); } -- 2.40.1