From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D4D2B15ACC for ; Wed, 20 Sep 2023 12:29:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56CFDC433C7; Wed, 20 Sep 2023 12:29:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695212994; bh=gflwZCc6hMGWyDWW5gbWA5Ye5q/5C6OAnb9mNfvE7/Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TxUT+2/EE5u3gCE/2kRi8R11jJr1LE4Xnj4AJefLMUopTIV7IonRDKhgO0eeAt3EM J3vqi/KFbLo3B83WAeQp8Mndjc53fwZr8o2Z7CoXWWbfdf3ypCWhvySEVwoXjwWu1B YRRS2AkXXpgxZNgi+ikeHhmKO02M5fdeAhIRbmTA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gaosheng Cui , Paul Moore , Sasha Levin Subject: [PATCH 5.4 121/367] audit: fix possible soft lockup in __audit_inode_child() Date: Wed, 20 Sep 2023 13:28:18 +0200 Message-ID: <20230920112901.782031107@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112858.471730572@linuxfoundation.org> References: <20230920112858.471730572@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gaosheng Cui [ Upstream commit b59bc6e37237e37eadf50cd5de369e913f524463 ] Tracefs or debugfs maybe cause hundreds to thousands of PATH records, too many PATH records maybe cause soft lockup. For example: 1. CONFIG_KASAN=y && CONFIG_PREEMPTION=n 2. auditctl -a exit,always -S open -k key 3. sysctl -w kernel.watchdog_thresh=5 4. mkdir /sys/kernel/debug/tracing/instances/test There may be a soft lockup as follows: watchdog: BUG: soft lockup - CPU#45 stuck for 7s! [mkdir:15498] Kernel panic - not syncing: softlockup: hung tasks Call trace: dump_backtrace+0x0/0x30c show_stack+0x20/0x30 dump_stack+0x11c/0x174 panic+0x27c/0x494 watchdog_timer_fn+0x2bc/0x390 __run_hrtimer+0x148/0x4fc __hrtimer_run_queues+0x154/0x210 hrtimer_interrupt+0x2c4/0x760 arch_timer_handler_phys+0x48/0x60 handle_percpu_devid_irq+0xe0/0x340 __handle_domain_irq+0xbc/0x130 gic_handle_irq+0x78/0x460 el1_irq+0xb8/0x140 __audit_inode_child+0x240/0x7bc tracefs_create_file+0x1b8/0x2a0 trace_create_file+0x18/0x50 event_create_dir+0x204/0x30c __trace_add_new_event+0xac/0x100 event_trace_add_tracer+0xa0/0x130 trace_array_create_dir+0x60/0x140 trace_array_create+0x1e0/0x370 instance_mkdir+0x90/0xd0 tracefs_syscall_mkdir+0x68/0xa0 vfs_mkdir+0x21c/0x34c do_mkdirat+0x1b4/0x1d4 __arm64_sys_mkdirat+0x4c/0x60 el0_svc_common.constprop.0+0xa8/0x240 do_el0_svc+0x8c/0xc0 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb4 el0_sync+0x160/0x180 Therefore, we add cond_resched() to __audit_inode_child() to fix it. Fixes: 5195d8e217a7 ("audit: dynamically allocate audit_names when not enough space is in the names array") Signed-off-by: Gaosheng Cui Signed-off-by: Paul Moore Signed-off-by: Sasha Levin --- kernel/auditsc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/auditsc.c b/kernel/auditsc.c index e8e90c0c49367..fc4223f30e847 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2161,6 +2161,8 @@ void __audit_inode_child(struct inode *parent, } } + cond_resched(); + /* is there a matching child entry? */ list_for_each_entry(n, &context->names_list, list) { /* can only match entries that have a name */ -- 2.40.1