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 4FAEAC61DA4 for ; Fri, 3 Feb 2023 10:17:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233294AbjBCKRl (ORCPT ); Fri, 3 Feb 2023 05:17:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232844AbjBCKR3 (ORCPT ); Fri, 3 Feb 2023 05:17:29 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87EDE9D04E; Fri, 3 Feb 2023 02:16:49 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id F25CBCE2FBC; Fri, 3 Feb 2023 10:16:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E86E2C433EF; Fri, 3 Feb 2023 10:16:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675419402; bh=6xVYWn1cB/jKDDvj/l2T8cfj6lfaX/08ysnB1mpPKr4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ycfrKEltm1DczW0B9aBN4sq+WFsYX7wcAYz2i/5wkVFiFZAJK+KrTuhFXKGqjATvh CjAX7BDRPmGwPAC3C9SLKLZiftdCIP3xdgrUH08/Ky8/92WLQpIpdRF/sjV09Ir4TP zvqjPf6yXgiyGXoCusACflDKuEkykIfkTSuj4jP4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jonathan Corbet , Andrew Morton , Baolin Wang , "Jason A. Donenfeld" , Eric Biggers , Huang Ying , Petr Mladek , tangmeng , "Guilherme G. Piccoli" , Tiezhu Yang , Sebastian Andrzej Siewior , linux-doc@vger.kernel.org, Luis Chamberlain , Kees Cook Subject: [PATCH 4.14 56/62] panic: Introduce warn_limit Date: Fri, 3 Feb 2023 11:12:52 +0100 Message-Id: <20230203101015.369640547@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230203101012.959398849@linuxfoundation.org> References: <20230203101012.959398849@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Kees Cook commit 9fc9e278a5c0b708eeffaf47d6eb0c82aa74ed78 upstream. Like oops_limit, add warn_limit for limiting the number of warnings when panic_on_warn is not set. Cc: Jonathan Corbet Cc: Andrew Morton Cc: Baolin Wang Cc: "Jason A. Donenfeld" Cc: Eric Biggers Cc: Huang Ying Cc: Petr Mladek Cc: tangmeng Cc: "Guilherme G. Piccoli" Cc: Tiezhu Yang Cc: Sebastian Andrzej Siewior Cc: linux-doc@vger.kernel.org Reviewed-by: Luis Chamberlain Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221117234328.594699-5-keescook@chromium.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- Documentation/sysctl/kernel.txt | 10 ++++++++++ kernel/panic.c | 27 +++++++++++++++++++++++++++ 2 files changed, 37 insertions(+) --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -94,6 +94,7 @@ show up in /proc/sys/kernel: - threads-max - unprivileged_bpf_disabled - unknown_nmi_panic +- warn_limit - watchdog - watchdog_thresh - version @@ -1072,6 +1073,15 @@ example. If a system hangs up, try pres ============================================================== +warn_limit: + +Number of kernel warnings after which the kernel should panic when +``panic_on_warn`` is not set. Setting this to 0 disables checking +the warning count. Setting this to 1 has the same effect as setting +``panic_on_warn=1``. The default value is 0. + +============================================================== + watchdog: This parameter can be used to disable or enable the soft lockup detector --- a/kernel/panic.c +++ b/kernel/panic.c @@ -39,6 +39,7 @@ static int pause_on_oops_flag; static DEFINE_SPINLOCK(pause_on_oops_lock); bool crash_kexec_post_notifiers; int panic_on_warn __read_mostly; +static unsigned int warn_limit __read_mostly; int panic_timeout = CONFIG_PANIC_TIMEOUT; EXPORT_SYMBOL_GPL(panic_timeout); @@ -47,6 +48,26 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list EXPORT_SYMBOL(panic_notifier_list); +#ifdef CONFIG_SYSCTL +static struct ctl_table kern_panic_table[] = { + { + .procname = "warn_limit", + .data = &warn_limit, + .maxlen = sizeof(warn_limit), + .mode = 0644, + .proc_handler = proc_douintvec, + }, + { } +}; + +static __init int kernel_panic_sysctls_init(void) +{ + register_sysctl_init("kernel", kern_panic_table); + return 0; +} +late_initcall(kernel_panic_sysctls_init); +#endif + static long no_blink(int state) { return 0; @@ -124,8 +145,14 @@ EXPORT_SYMBOL(nmi_panic); void check_panic_on_warn(const char *origin) { + static atomic_t warn_count = ATOMIC_INIT(0); + if (panic_on_warn) panic("%s: panic_on_warn set ...\n", origin); + + if (atomic_inc_return(&warn_count) >= READ_ONCE(warn_limit) && warn_limit) + panic("%s: system warned too often (kernel.warn_limit is %d)", + origin, warn_limit); } /**