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 A2E1CC001B0 for ; Mon, 24 Jul 2023 01:50:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232792AbjGXBuz (ORCPT ); Sun, 23 Jul 2023 21:50:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232793AbjGXBui (ORCPT ); Sun, 23 Jul 2023 21:50:38 -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 98D2E7A82; Sun, 23 Jul 2023 18:41:57 -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 9EF9660FB7; Mon, 24 Jul 2023 01:36:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0B14C433C8; Mon, 24 Jul 2023 01:36:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690162600; bh=dvDYr2R+oy3OEBXoXLstgmhQ4tUTeDxO2FDYE51Y9BU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=km79bz3BfxL4WTwijwJWvPT1sX+YqTEfkM694eyyYZM6WaW3rUHgSFw+ydKWsHsM9 5GPrebN+B0vj6tbJls4V8V8PAGg45MhJJPe9VV2HjIxCK4Rkgv52s5Xw6rpj11ou28 9vjF61EulccLezTq64y0gcygTkfSLofdiF3HkJIDW0XC7mdsLRH7BejtKS7XV2mmUm RUQ6vnxrtmpaPFUNuaKd4FLSeGQ0oULssJjbMfLUPhIFvKsdwjsdY0nIs7AxTC1NHL 0jlo22OD3QV+lxgWSg0vBb2yLmw3JvsM2MiSwSHQo3Pyo9G2JUa7Ay+WL1RCzzP9Ar wI6+ybMYGg1vA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tuo Li , BassCheck , Andreas Gruenbacher , Sasha Levin , swhiteho@redhat.com, rpeterso@redhat.com, cluster-devel@redhat.com Subject: [PATCH AUTOSEL 4.14 5/9] gfs2: Fix possible data races in gfs2_show_options() Date: Sun, 23 Jul 2023 21:35:47 -0400 Message-Id: <20230724013554.2334965-5-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230724013554.2334965-1-sashal@kernel.org> References: <20230724013554.2334965-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 4.14.320 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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 56bfed0a58731..92de2f645c467 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -1363,7 +1363,14 @@ 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"); @@ -1418,17 +1425,14 @@ 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) { -- 2.39.2