From patchwork Thu Feb 2 05:26:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13125324 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 CB16FC6379F for ; Thu, 2 Feb 2023 05:29:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230251AbjBBF3I (ORCPT ); Thu, 2 Feb 2023 00:29:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231691AbjBBF2Y (ORCPT ); Thu, 2 Feb 2023 00:28:24 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8310C1F5D6; Wed, 1 Feb 2023 21:28:10 -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 dfw.source.kernel.org (Postfix) with ESMTPS id CBFD8615EB; Thu, 2 Feb 2023 05:28:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C096C4339E; Thu, 2 Feb 2023 05:28:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675315689; bh=wDzo53Dl0UDwP01U6Ffmf8hrLpT0FCIt+byjVDuB7aY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LlplLbAJlnEemvNaUO2Mz2C0sOMCIG1zXP6tRmNnDsU+D6CxCwFp5IeajaTiCs/2F DmfoAsF5RcQSOP7rw7NMOJrgBnQNHU3UzDgM+uRY3XEAXV4QB57erhrTAemyHhCZsl YSBSgS4+zaiXIIhidKtDXgwOolhfXQjwrZYRBqLbGzBZlRu+yAX0OhSUV6S+3YtL4N nTntuRWBnqbgcPH2od+JnCFH1K1lXb22QX+3LxU4sbAM00ConG16KSuR1iuqN/mnq8 zvxv6jeHbT78QgFezP52ak05ae8BA1O+Ozzr1EEJDyTL7ZqnQGWPi64/yd0hlmQCsz DAr1sLanvmqWw== From: Eric Biggers To: stable@vger.kernel.org Cc: Harshit Mogalapalli , Kees Cook , SeongJae Park , Seth Jenkins , Jann Horn , "Eric W . Biederman" , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, 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 Subject: [PATCH 4.19 13/16] panic: Introduce warn_limit Date: Wed, 1 Feb 2023 21:26:01 -0800 Message-Id: <20230202052604.179184-14-ebiggers@kernel.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230202052604.179184-1-ebiggers@kernel.org> References: <20230202052604.179184-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@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 --- Documentation/sysctl/kernel.txt | 10 ++++++++++ kernel/panic.c | 27 +++++++++++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index e1d375df4f286..c8d3dbda3c1e2 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -97,6 +97,7 @@ show up in /proc/sys/kernel: - threads-max - unprivileged_bpf_disabled - unknown_nmi_panic +- warn_limit - watchdog - watchdog_thresh - version @@ -1114,6 +1115,15 @@ example. If a system hangs up, try pressing the NMI switch. ============================================================== +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 diff --git a/kernel/panic.c b/kernel/panic.c index 08b8adc55b2bf..d1a5360262f04 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -42,6 +42,7 @@ 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); @@ -50,6 +51,26 @@ 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; @@ -127,8 +148,14 @@ 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); } /**