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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D9F1C433EF for ; Mon, 15 Nov 2021 16:58:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3C0661BD2 for ; Mon, 15 Nov 2021 16:58:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231500AbhKORBe (ORCPT ); Mon, 15 Nov 2021 12:01:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231845AbhKORBT (ORCPT ); Mon, 15 Nov 2021 12:01:19 -0500 Received: from mail-qt1-x82e.google.com (mail-qt1-x82e.google.com [IPv6:2607:f8b0:4864:20::82e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 957B5C061767 for ; Mon, 15 Nov 2021 08:58:20 -0800 (PST) Received: by mail-qt1-x82e.google.com with SMTP id f20so15906635qtb.4 for ; Mon, 15 Nov 2021 08:58:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=uRK4hkiTZUWAj8cllnANNjoMKBWhSK9KFUzOvcsNuMo=; b=gRW0T62HV+UT9h6Yk9u86KO0O3WB3c6UhXA/f86Z5X7AptFebxL1MEk69/tiexmBwh ZvzGOXFmPKGSY54l7mNkhTa7Ec3BU/dmtgMMtRdjQ/q7G8NA/OSjdSPk/xkWR7Kugcqn 9ORZQtY2a5m43CttZTNfVauM7FxfzMPBVn8DBHyixQf/JZvj7BxQ+NMM6OwhfkH1ml5l FmLbpnemQOv3QQ7JpLiBUQQ+b82R3BW5+zbzpt5Fh577tQQI51gslBJOtFqgucuw556L r+TSRVppHEHcr9AYSmuD2B7ECDirkfzz+qReTmndefTSTHbuh3MbotV9JnK8x4t0nRC4 /lTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=uRK4hkiTZUWAj8cllnANNjoMKBWhSK9KFUzOvcsNuMo=; b=C+p99S4F8gN22QV1GCWJRce3lMEPRNVVjvV8d/cfS6eM5BeqnziCobNXxYdP64hMUS jNVF3X/M6j1d6PnCfIR412oNcIcEa+xXL0snXnDmXl9c6U5DCikOos4GKratymmx4fOI 3RRREHCkDXbDebOia0mwM+gHvVHe6LYBnqstv+EAkYRW5L3PiJWkkEKTEOCZpPshP15n HdKFBammhnaiHKWwCyA+mqeAm7HcixrPZBz97GV0kWTDU6gkrZ1e0vSpcJ6LtuHEEdEb sRDdMOdf12Ai4oRBYICrhEc/bwcnNltQ0lxQbKleSJaM24Ssk6k20GxFVa4eTGe78GPD lE2A== X-Gm-Message-State: AOAM533d5NrnSrhFYQPzymkgxDL0ZG27gjHqmVHwPtPr5wnp+OSQptgJ /2REr6MyHIVvNIcpRr220D8PO+KdiiYvWA== X-Google-Smtp-Source: ABdhPJy+IfTqyFfTCuPJMAGG1KY5pS7fFY8nW3jZafxG32VtoYNRkGZ4fADB8IxUo9qxJvPqIBGVFw== X-Received: by 2002:a05:622a:11d1:: with SMTP id n17mr501421qtk.154.1636995499441; Mon, 15 Nov 2021 08:58:19 -0800 (PST) Received: from gouda.nowheycreamery.com ([2601:401:100:a3a:aa6d:aaff:fe2e:8a6a]) by smtp.gmail.com with ESMTPSA id v7sm6988472qki.98.2021.11.15.08.58.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Nov 2021 08:58:19 -0800 (PST) Sender: Anna Schumaker From: schumaker.anna@gmail.com X-Google-Original-From: Anna.Schumaker@Netapp.com To: Trond.Myklebust@hammerspace.com, linux-nfs@vger.kernel.org Cc: Anna.Schumaker@Netapp.com Subject: [PATCH 1/3] sunrpc: Fix potential race conditions in rpc_sysfs_xprt_state_change() Date: Mon, 15 Nov 2021 11:58:16 -0500 Message-Id: <20211115165818.2583501-1-Anna.Schumaker@Netapp.com> X-Mailer: git-send-email 2.33.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Anna Schumaker 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 --- 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 77e7d011c1ab..8f309bcdf84f 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; -- 2.33.1