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 84E03C433EF for ; Thu, 3 Feb 2022 20:30:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354282AbiBCUad (ORCPT ); Thu, 3 Feb 2022 15:30:33 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:33244 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354157AbiBCUaL (ORCPT ); Thu, 3 Feb 2022 15:30:11 -0500 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 ams.source.kernel.org (Postfix) with ESMTPS id 3F4D8B835A5; Thu, 3 Feb 2022 20:30:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4DBAC340E8; Thu, 3 Feb 2022 20:30:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643920208; bh=IbpWskCq2JHkLWQanpF+VpG9Upo9c0eksO/WL2vpMrg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YjiOCi6w5z9z26OcJP2Z6Rs9I5VsdRXHKwHo9XF+Gqumf524upJdIElDITiDoKrSV BlA1Za9teESGmviQoQ5qqO0x0KLdsuEaUxQWLz47YZQH8Eomdti15h+0NqAw93H4+x JZ2w5UKYMfm6lwm0qddPM/cc+JLPbtagmlqyFNqdQpRBcocn004xMod8MFRiyzVDHF nOAM6olrJiCkQ/Ezs+xSGSHjzEyXAK+Pxkc5mdTl7s6lgSMfRrAGprWiEQqEuHmtSP K/Cn/92mgJn78b6uY6IlHWe9Z/L6APKBVKdyOL5pVoifkK7ltNCnZZT3zAMQXd6nDj vhoPm+bTA4w4Q== 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 5.16 13/52] sunrpc: Fix potential race conditions in rpc_sysfs_xprt_state_change() Date: Thu, 3 Feb 2022 15:29:07 -0500 Message-Id: <20220203202947.2304-13-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220203202947.2304-1-sashal@kernel.org> References: <20220203202947.2304-1-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: netdev@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 77e7d011c1ab1..8f309bcdf84fe 100644 --- a/net/sunrpc/sysfs.c +++ b/net/sunrpc/sysfs.c @@ -309,25 +309,28 @@ 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