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 47A72C83F1D for ; Mon, 28 Aug 2023 10:36:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231598AbjH1KgL (ORCPT ); Mon, 28 Aug 2023 06:36:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231650AbjH1Kfy (ORCPT ); Mon, 28 Aug 2023 06:35:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E81A5115 for ; Mon, 28 Aug 2023 03:35:51 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 873BD61562 for ; Mon, 28 Aug 2023 10:35:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72896C433C7; Mon, 28 Aug 2023 10:35:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1693218951; bh=zOPKIohgsEBzkCLGlo7jKLGtjyEsQFQrpVUEGw+llmI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nDwHZ37ZDdYC9QYc/U5f+wm/40HmwhE5mp2h/x6Zz7LBnoOUCJlLrtAyBthZDTgxv vXwuwMbztfap3AkM3rluKL/pJ5Nu3uGibbAU4TW3YhKbDwN3N6cnB9/N9Q0QEaqPMC i7zl5TsemwVkdszV4NU3V67/4gdIaNwZGiUj8Rko= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, BassCheck , Tuo Li , Andreas Gruenbacher , Sasha Levin Subject: [PATCH 5.4 020/158] gfs2: Fix possible data races in gfs2_show_options() Date: Mon, 28 Aug 2023 12:11:57 +0200 Message-ID: <20230828101158.027096744@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230828101157.322319621@linuxfoundation.org> References: <20230828101157.322319621@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tuo Li [ Upstream commit 6fa0a72cbbe45db4ed967a51f9e6f4e3afe61d20 ] Some fields such as gt_logd_secs of the struct gfs2_tune are accessed without holding the lock gt_spin in gfs2_show_options(): val = sdp->sd_tune.gt_logd_secs; if (val != 30) seq_printf(s, ",commit=%d", val); And thus can cause data races when gfs2_show_options() and other functions such as gfs2_reconfigure() are concurrently executed: spin_lock(>->gt_spin); gt->gt_logd_secs = newargs->ar_commit; To fix these possible data races, the lock sdp->sd_tune.gt_spin is acquired before accessing the fields of gfs2_tune and released after these accesses. Further changes by Andreas: - Don't hold the spin lock over the seq_printf operations. Reported-by: BassCheck Signed-off-by: Tuo Li Signed-off-by: Andreas Gruenbacher Signed-off-by: Sasha Levin --- fs/gfs2/super.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index baf0a70460c03..15e757f763806 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -1046,7 +1046,14 @@ static int gfs2_show_options(struct seq_file *s, struct dentry *root) { struct gfs2_sbd *sdp = root->d_sb->s_fs_info; struct gfs2_args *args = &sdp->sd_args; - int val; + unsigned int logd_secs, statfs_slow, statfs_quantum, quota_quantum; + + spin_lock(&sdp->sd_tune.gt_spin); + logd_secs = sdp->sd_tune.gt_logd_secs; + quota_quantum = sdp->sd_tune.gt_quota_quantum; + statfs_quantum = sdp->sd_tune.gt_statfs_quantum; + statfs_slow = sdp->sd_tune.gt_statfs_slow; + spin_unlock(&sdp->sd_tune.gt_spin); if (is_ancestor(root, sdp->sd_master_dir)) seq_puts(s, ",meta"); @@ -1101,17 +1108,14 @@ static int gfs2_show_options(struct seq_file *s, struct dentry *root) } if (args->ar_discard) seq_puts(s, ",discard"); - val = sdp->sd_tune.gt_logd_secs; - if (val != 30) - seq_printf(s, ",commit=%d", val); - val = sdp->sd_tune.gt_statfs_quantum; - if (val != 30) - seq_printf(s, ",statfs_quantum=%d", val); - else if (sdp->sd_tune.gt_statfs_slow) + if (logd_secs != 30) + seq_printf(s, ",commit=%d", logd_secs); + if (statfs_quantum != 30) + seq_printf(s, ",statfs_quantum=%d", statfs_quantum); + else if (statfs_slow) seq_puts(s, ",statfs_quantum=0"); - val = sdp->sd_tune.gt_quota_quantum; - if (val != 60) - seq_printf(s, ",quota_quantum=%d", val); + if (quota_quantum != 60) + seq_printf(s, ",quota_quantum=%d", quota_quantum); if (args->ar_statfs_percent) seq_printf(s, ",statfs_percent=%d", args->ar_statfs_percent); if (args->ar_errors != GFS2_ERRORS_DEFAULT) { -- 2.40.1