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 62915C433EF for ; Tue, 19 Jul 2022 12:20:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235165AbiGSMU2 (ORCPT ); Tue, 19 Jul 2022 08:20:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239121AbiGSMRr (ORCPT ); Tue, 19 Jul 2022 08:17:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2FB157216; Tue, 19 Jul 2022 05:06:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 766A4616F3; Tue, 19 Jul 2022 12:06:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5AA7DC341C6; Tue, 19 Jul 2022 12:06:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658232397; bh=jBwL2Hzav/uiDZZWKt1O+svrUTp3QIg2jT5a2Uo04Qk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VIYA+ABAjCDUr8Iwjx9pxAW9/IIjMIvcpQDACKIjcWbNT9fzsdw6fbHIWpJ6EkzQf O16rTHGrzM4kNsgIQlXYSRujKGbHnSLc3AesPCVJraf6MkSD/NbjbcC+T8pVDRWrUo SmPfukWFup4Gpiw8xj2n+cUzKCu78AXCZwMuF3cw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuniyuki Iwashima , "David S. Miller" , Sasha Levin Subject: [PATCH 5.10 043/112] sysctl: Fix data races in proc_douintvec(). Date: Tue, 19 Jul 2022 13:53:36 +0200 Message-Id: <20220719114630.574536484@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220719114626.156073229@linuxfoundation.org> References: <20220719114626.156073229@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kuniyuki Iwashima [ Upstream commit 4762b532ec9539755aab61445d5da6e1926ccb99 ] A sysctl variable is accessed concurrently, and there is always a chance of data-race. So, all readers and writers need some basic protection to avoid load/store-tearing. This patch changes proc_douintvec() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_douintvec() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side. Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- kernel/sysctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 81657b13bd53..30681afbdb70 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -583,9 +583,9 @@ static int do_proc_douintvec_conv(unsigned long *lvalp, if (write) { if (*lvalp > UINT_MAX) return -EINVAL; - *valp = *lvalp; + WRITE_ONCE(*valp, *lvalp); } else { - unsigned int val = *valp; + unsigned int val = READ_ONCE(*valp); *lvalp = (unsigned long)val; } return 0; -- 2.35.1