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 50515C61DA4 for ; Mon, 30 Jan 2023 14:19:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237611AbjA3OTR (ORCPT ); Mon, 30 Jan 2023 09:19:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237624AbjA3OSl (ORCPT ); Mon, 30 Jan 2023 09:18:41 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04BE33EC72; Mon, 30 Jan 2023 06:17:49 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 072326108B; Mon, 30 Jan 2023 14:17:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD977C433EF; Mon, 30 Jan 2023 14:17:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675088262; bh=5ZzNBh+M2CSjwwOyKvU5MEoLDHOU97ObdPOPhIcH/hc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=skDIB2JRgubCbyo7Xnyu6ACeSFk4kcqfRPra1ye3JAOm2lBlrA9eLVwlD21K5w34B 9mlWcZ0BTA+dQfRwxw70iVSPbvyhDYv5ITBV1NLPz5GaQh8cz25Pr3bK5oy5KfU5wZ JwIZ6sE6nzw9swKEoa9whga71Ql24GPAVZt/6Ngc= 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 , Sasha Levin Subject: [PATCH 5.15 139/204] panic: Introduce warn_limit Date: Mon, 30 Jan 2023 14:51:44 +0100 Message-Id: <20230130134322.658787288@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134316.327556078@linuxfoundation.org> References: <20230130134316.327556078@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: Sasha Levin --- Documentation/admin-guide/sysctl/kernel.rst | 10 ++++++++++ kernel/panic.c | 14 ++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index d6f1d3892e71..48b91c485c99 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -1494,6 +1494,16 @@ entry will default to 2 instead of 0. 2 Unprivileged calls to ``bpf()`` are disabled = ============================================================= + +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 ======== diff --git a/kernel/panic.c b/kernel/panic.c index bf0324941e43..604d7ad77042 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -57,6 +57,7 @@ bool crash_kexec_post_notifiers; int panic_on_warn __read_mostly; unsigned long panic_on_taint; bool panic_on_taint_nousertaint = false; +static unsigned int warn_limit __read_mostly; int panic_timeout = CONFIG_PANIC_TIMEOUT; EXPORT_SYMBOL_GPL(panic_timeout); @@ -86,6 +87,13 @@ static struct ctl_table kern_panic_table[] = { .extra2 = SYSCTL_ONE, }, #endif + { + .procname = "warn_limit", + .data = &warn_limit, + .maxlen = sizeof(warn_limit), + .mode = 0644, + .proc_handler = proc_douintvec, + }, { } }; @@ -195,8 +203,14 @@ static void panic_print_sys_info(void) 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); } /** -- 2.39.0