From nobody Fri Sep 5 20:07:57 2025 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 BD4B7C32772 for ; Tue, 23 Aug 2022 11:48:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358449AbiHWLst (ORCPT ); Tue, 23 Aug 2022 07:48:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358142AbiHWLpN (ORCPT ); Tue, 23 Aug 2022 07:45:13 -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 6B995D1272; Tue, 23 Aug 2022 02:30:05 -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 A451861381; Tue, 23 Aug 2022 09:30:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEDD8C433C1; Tue, 23 Aug 2022 09:30:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661247003; bh=UCYycxyPUwO1hHOBKfBA1QUnk84cOVlOhcqdGlDU2ck=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xdCrBhG6aHoUALTksWzXhKOFwtaO6C1T0EFpvQ3Qk3niTB7SozxD71sNvMPvrR/ON fL0D7mXi7pgf+/RNiK8ijP7rIdWrCArzLOQRcdHLMnNzn8DpMDzQpyaaruxZNbX13i 7U0irKUeLKcT4xJGEqU7U5WuetvLKhV4a7Ug9vAk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , "David S. Miller" Subject: [PATCH 5.4 287/389] rds: add missing barrier to release_refill Date: Tue, 23 Aug 2022 10:26:05 +0200 Message-Id: <20220823080127.533786856@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080115.331990024@linuxfoundation.org> References: <20220823080115.331990024@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Mikulas Patocka commit 9f414eb409daf4f778f011cf8266d36896bb930b upstream. The functions clear_bit and set_bit do not imply a memory barrier, thus it may be possible that the waitqueue_active function (which does not take any locks) is moved before clear_bit and it could miss a wakeup event. Fix this bug by adding a memory barrier after clear_bit. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/rds/ib_recv.c | 1 + 1 file changed, 1 insertion(+) --- a/net/rds/ib_recv.c +++ b/net/rds/ib_recv.c @@ -363,6 +363,7 @@ static int acquire_refill(struct rds_con static void release_refill(struct rds_connection *conn) { clear_bit(RDS_RECV_REFILL, &conn->c_flags); + smp_mb__after_atomic(); =20 /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a * hot path and finding waiters is very rare. We don't want to walk