From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 489E115AE3 for ; Wed, 9 Aug 2023 10:45:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD07FC433C8; Wed, 9 Aug 2023 10:45:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691577954; bh=iBTsONJIbCbB1rXQOZYOHcTQJJlvgXaJWHOyNoCLtRc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2d9/+iP3+azhGrDeCjLph9fEZUZ+fGcTCwd6IuzzxpGHUi9v52TtevaJcTYZ8bH4/ Kj0jGY8N+BKilcz34dH73GroicoRzs/n9U2FZ9/3BDq8C/nW76Xy5laIL3rZu2zIlT gro3cSawQZZ5jgQvCD/1GqjZdNjXdxnoU07jfarA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , "David S. Miller" , Sasha Levin Subject: [PATCH 6.4 053/165] net: annotate data-races around sk->sk_max_pacing_rate Date: Wed, 9 Aug 2023 12:39:44 +0200 Message-ID: <20230809103644.552259900@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103642.720851262@linuxfoundation.org> References: <20230809103642.720851262@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Eric Dumazet [ Upstream commit ea7f45ef77b39e72244d282e47f6cb1ef4135cd2 ] sk_getsockopt() runs locklessly. This means sk->sk_max_pacing_rate can be read while other threads are changing its value. Fixes: 62748f32d501 ("net: introduce SO_MAX_PACING_RATE") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/sock.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index b25511e7e8103..b87f498072251 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1428,7 +1428,8 @@ int sk_setsockopt(struct sock *sk, int level, int optname, cmpxchg(&sk->sk_pacing_status, SK_PACING_NONE, SK_PACING_NEEDED); - sk->sk_max_pacing_rate = ulval; + /* Pairs with READ_ONCE() from sk_getsockopt() */ + WRITE_ONCE(sk->sk_max_pacing_rate, ulval); sk->sk_pacing_rate = min(sk->sk_pacing_rate, ulval); break; } @@ -1855,12 +1856,14 @@ int sk_getsockopt(struct sock *sk, int level, int optname, #endif case SO_MAX_PACING_RATE: + /* The READ_ONCE() pair with the WRITE_ONCE() in sk_setsockopt() */ if (sizeof(v.ulval) != sizeof(v.val) && len >= sizeof(v.ulval)) { lv = sizeof(v.ulval); - v.ulval = sk->sk_max_pacing_rate; + v.ulval = READ_ONCE(sk->sk_max_pacing_rate); } else { /* 32bit version */ - v.val = min_t(unsigned long, sk->sk_max_pacing_rate, ~0U); + v.val = min_t(unsigned long, ~0U, + READ_ONCE(sk->sk_max_pacing_rate)); } break; -- 2.40.1