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 0E00DC001E0 for ; Mon, 24 Jul 2023 01:38:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230508AbjGXBhy (ORCPT ); Sun, 23 Jul 2023 21:37:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231895AbjGXBhU (ORCPT ); Sun, 23 Jul 2023 21:37:20 -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 276902715; Sun, 23 Jul 2023 18:33:29 -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 32D6260F88; Mon, 24 Jul 2023 01:32:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA450C433C9; Mon, 24 Jul 2023 01:32:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690162322; bh=jG3E2QudLA5H34gLF614G+3baKTN9ayy3cPrW+chbr0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kp7aeupccF098hQja+XaPDNYLrlkk/iTT+3aFk4mV/fgRf78Xz58p94gs6TuIpzbO D30JP7lsidFkm+EUKYvkrM2WxVjHw0cTIgN5CCCo1vyMLjc3vDpoxLaBMu6d3RMlUJ gyG74R0QsXlHjZw+DMKioWw1ikXlRFSo8PdedmtwDOABSsWw+sgZtXNM+fJezBl9gB KjMFR3PDc/8Eh6KcvtxNYTF5OvX11XUs2Iox75geWQxUrk7VmYmlwC29rEBztt06hg wkCHEW8q2zpV7oI8WhK1+JbhoQ1/qj/RR6wDOqnGWlUdurLbVRk0r/F3WMK6mzIwZz xUnMXlHJ28Gvw== 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 6.4 15/40] gfs2: Fix possible data races in gfs2_show_options() Date: Sun, 23 Jul 2023 21:31:15 -0400 Message-Id: <20230724013140.2327815-15-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230724013140.2327815-1-sashal@kernel.org> References: <20230724013140.2327815-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.4.5 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 a84bf6444bba9..204ba7f8417e6 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -1004,7 +1004,14 @@ 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"); @@ -1059,17 +1066,14 @@ 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