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 8F40BC43217 for ; Thu, 3 Feb 2022 20:36:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355462AbiBCUfx (ORCPT ); Thu, 3 Feb 2022 15:35:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354098AbiBCUdn (ORCPT ); Thu, 3 Feb 2022 15:33:43 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5BCDC061793; Thu, 3 Feb 2022 12:33:08 -0800 (PST) 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 52A1A61A04; Thu, 3 Feb 2022 20:33:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 940DEC340EF; Thu, 3 Feb 2022 20:33:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643920387; bh=0y/IZM+9R7R9WIPYSINAAR4GixoHnxscFamQq446Yng=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BzvcUENgy1RX49AMRjkBaQ58+LAQ2sGsNadUiVU5bUonneUmXpU0UxJZvvHE/+a8r i8+I/mHssKMCjNZ2cNPP3u+o8eGVY7wtP5EcW3FA0ZAMfTTigsaYj5eZkvdTQs9vuq r80P6vZWKtPzol+0HD96jIXa3omTaFhkkz8qZ9ffphO30yU2SAHFSddI74obXVPCiY VrZw4M7rFNIbNGC1vYJp58KxtwcAdmyMxa/Qw/p+8T1q4kTNjinzlEE3Dxf074drqb RslYz4ihLKDoyV4qL4LzyB0ihbKW7zK5qAFcFT2IuFjh118YGwv9FAQtsr8IjpbiU1 Ja0WVwKf6Faug== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Anna Schumaker , Sasha Levin , trond.myklebust@hammerspace.com, anna.schumaker@netapp.com, chuck.lever@oracle.com, davem@davemloft.net, kuba@kernel.org, linux-nfs@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 13/41] sunrpc: Fix potential race conditions in rpc_sysfs_xprt_state_change() Date: Thu, 3 Feb 2022 15:32:17 -0500 Message-Id: <20220203203245.3007-13-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220203203245.3007-1-sashal@kernel.org> References: <20220203203245.3007-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anna Schumaker [ Upstream commit 1a48db3fef499f615b56093947ec4b0d3d8e3021 ] We need to use test_and_set_bit() when changing xprt state flags to avoid potentially getting xps->xps_nactive out of sync. Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- net/sunrpc/sysfs.c | 35 +++++++++++++++++++---------------- 1 file changed, 19 insertions(+), 16 deletions(-) diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c index 379cf0e4d965b..326a31422a3c1 100644 --- a/net/sunrpc/sysfs.c +++ b/net/sunrpc/sysfs.c @@ -305,25 +305,28 @@ static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj, goto release_tasks; } if (offline) { - set_bit(XPRT_OFFLINE, &xprt->state); - spin_lock(&xps->xps_lock); - xps->xps_nactive--; - spin_unlock(&xps->xps_lock); + if (!test_and_set_bit(XPRT_OFFLINE, &xprt->state)) { + spin_lock(&xps->xps_lock); + xps->xps_nactive--; + spin_unlock(&xps->xps_lock); + } } else if (online) { - clear_bit(XPRT_OFFLINE, &xprt->state); - spin_lock(&xps->xps_lock); - xps->xps_nactive++; - spin_unlock(&xps->xps_lock); + if (test_and_clear_bit(XPRT_OFFLINE, &xprt->state)) { + spin_lock(&xps->xps_lock); + xps->xps_nactive++; + spin_unlock(&xps->xps_lock); + } } else if (remove) { if (test_bit(XPRT_OFFLINE, &xprt->state)) { - set_bit(XPRT_REMOVE, &xprt->state); - xprt_force_disconnect(xprt); - if (test_bit(XPRT_CONNECTED, &xprt->state)) { - if (!xprt->sending.qlen && - !xprt->pending.qlen && - !xprt->backlog.qlen && - !atomic_long_read(&xprt->queuelen)) - rpc_xprt_switch_remove_xprt(xps, xprt); + if (!test_and_set_bit(XPRT_REMOVE, &xprt->state)) { + xprt_force_disconnect(xprt); + if (test_bit(XPRT_CONNECTED, &xprt->state)) { + if (!xprt->sending.qlen && + !xprt->pending.qlen && + !xprt->backlog.qlen && + !atomic_long_read(&xprt->queuelen)) + rpc_xprt_switch_remove_xprt(xps, xprt); + } } } else { count = -EINVAL; -- 2.34.1