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 60A66C433F5 for ; Fri, 25 Mar 2022 01:35:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350491AbiCYBhM (ORCPT ); Thu, 24 Mar 2022 21:37:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357531AbiCYBf5 (ORCPT ); Thu, 24 Mar 2022 21:35:57 -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 209D23B573 for ; Thu, 24 Mar 2022 18:34:17 -0700 (PDT) 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 B084260A75 for ; Fri, 25 Mar 2022 01:34:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 14BFEC340EC; Fri, 25 Mar 2022 01:34:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648172056; bh=cJ4+Eh/hPzpmzvMDfz3MMRiBW9EhElmtbJObyF4zMmE=; h=Date:To:From:Subject:From; b=m2VASoL6i+BCbtYZAK0IP1E7OYb836y5EWPhv72lv7Xcijwmp6Z4x1uE0BtpZyneV Q3wS4MAEbVDUL+lFdoAwOaf6lfK0oa/wsGn6kL9f9sF9zcA80WVs4FtdgaV0w2Euxf 6oFJa4eZCVzdEjJ6xNVRKXywB5Pu/KiYv59tlHPE= Date: Thu, 24 Mar 2022 18:34:15 -0700 To: mm-commits@vger.kernel.org, yzaikin@google.com, siglesias@igalia.com, mcgrof@kernel.org, keescook@chromium.org, feng.tang@intel.com, gpiccoli@igalia.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged] panic-add-option-to-dump-all-cpus-backtraces-in-panic_print.patch removed from -mm tree Message-Id: <20220325013416.14BFEC340EC@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: panic: add option to dump all CPUs backtraces in panic_print has been removed from the -mm tree. Its filename was panic-add-option-to-dump-all-cpus-backtraces-in-panic_print.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: "Guilherme G. Piccoli" Subject: panic: add option to dump all CPUs backtraces in panic_print Currently the "panic_print" parameter/sysctl allows some interesting debug information to be printed during a panic event. This is useful for example in cases the user cannot kdump due to resource limits, or if the user collects panic logs in a serial output (or pstore) and prefers a fast reboot instead of a kdump. Happens that currently there's no way to see all CPUs backtraces in a panic using "panic_print" on architectures that support that. We do have "oops_all_cpu_backtrace" sysctl, but although partially overlapping in the functionality, they are orthogonal in nature: "panic_print" is a panic tuning (and we have panics without oopses, like direct calls to panic() or maybe other paths that don't go through oops_enter() function), and the original purpose of "oops_all_cpu_backtrace" is to provide more information on oopses for cases in which the users desire to continue running the kernel even after an oops, i.e., used in non-panic scenarios. So, we hereby introduce an additional bit for "panic_print" to allow dumping the CPUs backtraces during a panic event. Link: https://lkml.kernel.org/r/20211109202848.610874-3-gpiccoli@igalia.com Signed-off-by: Guilherme G. Piccoli Reviewed-by: Feng Tang Cc: Iurii Zaikin Cc: Kees Cook Cc: Luis Chamberlain Cc: Samuel Iglesias Gonsalvez Signed-off-by: Andrew Morton --- Documentation/admin-guide/kernel-parameters.txt | 1 + Documentation/admin-guide/sysctl/kernel.rst | 1 + kernel/panic.c | 4 ++++ 3 files changed, 6 insertions(+) --- a/Documentation/admin-guide/kernel-parameters.txt~panic-add-option-to-dump-all-cpus-backtraces-in-panic_print +++ a/Documentation/admin-guide/kernel-parameters.txt @@ -3726,6 +3726,7 @@ bit 3: print locks info if CONFIG_LOCKDEP is on bit 4: print ftrace buffer bit 5: print all printk messages in buffer + bit 6: print all CPUs backtrace (if available in the arch) panic_on_taint= Bitmask for conditionally calling panic() in add_taint() Format: [,nousertaint] --- a/Documentation/admin-guide/sysctl/kernel.rst~panic-add-option-to-dump-all-cpus-backtraces-in-panic_print +++ a/Documentation/admin-guide/sysctl/kernel.rst @@ -807,6 +807,7 @@ bit 2 print timer info bit 3 print locks info if ``CONFIG_LOCKDEP`` is on bit 4 print ftrace buffer bit 5 print all printk messages in buffer +bit 6 print all CPUs backtrace (if available in the arch) ===== ============================================ So for example to print tasks and memory info on panic, user can:: --- a/kernel/panic.c~panic-add-option-to-dump-all-cpus-backtraces-in-panic_print +++ a/kernel/panic.c @@ -66,6 +66,7 @@ EXPORT_SYMBOL_GPL(panic_timeout); #define PANIC_PRINT_LOCK_INFO 0x00000008 #define PANIC_PRINT_FTRACE_INFO 0x00000010 #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 +#define PANIC_PRINT_ALL_CPU_BT 0x00000040 unsigned long panic_print; ATOMIC_NOTIFIER_HEAD(panic_notifier_list); @@ -152,6 +153,9 @@ static void panic_print_sys_info(void) if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) console_flush_on_panic(CONSOLE_REPLAY_ALL); + if (panic_print & PANIC_PRINT_ALL_CPU_BT) + trigger_all_cpu_backtrace(); + if (panic_print & PANIC_PRINT_TASK_INFO) show_state(); _ Patches currently in -mm which might be from gpiccoli@igalia.com are