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 8198CC433F5 for ; Mon, 17 Jan 2022 03:34:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236996AbiAQDeG (ORCPT ); Sun, 16 Jan 2022 22:34:06 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:60323 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236991AbiAQDeB (ORCPT ); Sun, 16 Jan 2022 22:34:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1642390441; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Z7kmAQx1W86wiixFNxYrN6XgsdmCVXWqG3Iw078BpWE=; b=OropG9gJiu+SjKyc8gqc8GUiV4eVWl6zEHDczVqp/F7qbZAP8x4WnNxIZIUbhLe04F0hvP CS0UNtWZGNbkVXF1o4pY648M0fEXLIljlCOTvMqc2KXiSrJ3QuK1kgRQmbb087pidNvJti wkvmyHeKn3REw+mcPqbTIHu1BoiuRA4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-628-dV9BwejdPMe6Qe2iDsvMwg-1; Sun, 16 Jan 2022 22:33:55 -0500 X-MC-Unique: dV9BwejdPMe6Qe2iDsvMwg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 631B91853033; Mon, 17 Jan 2022 03:33:53 +0000 (UTC) Received: from localhost (ovpn-12-67.pek2.redhat.com [10.72.12.67]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A685E5E272; Mon, 17 Jan 2022 03:33:46 +0000 (UTC) Date: Mon, 17 Jan 2022 11:33:44 +0800 From: Baoquan He To: "Guilherme G. Piccoli" Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, pmladek@suse.com, kernel@gpiccoli.net, senozhatsky@chromium.org, rostedt@goodmis.org, john.ogness@linutronix.de, feng.tang@intel.com, kexec@lists.infradead.org, dyoung@redhat.com, keescook@chromium.org, anton@enomsg.org, ccross@android.com, tony.luck@intel.com Subject: Re: [PATCH V3] panic: Move panic_print before kmsg dumpers Message-ID: <20220117033344.GA2523@MiWiFi-R3L-srv> References: <20220114183046.428796-1-gpiccoli@igalia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220114183046.428796-1-gpiccoli@igalia.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/14/22 at 03:30pm, Guilherme G. Piccoli wrote: ...... > .../admin-guide/kernel-parameters.txt | 4 ++++ > kernel/panic.c | 22 ++++++++++++++----- > 2 files changed, 21 insertions(+), 5 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index a069d8fe2fee..0f5cbe141bfd 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3727,6 +3727,10 @@ > bit 4: print ftrace buffer > bit 5: print all printk messages in buffer > bit 6: print all CPUs backtrace (if available in the arch) > + *Be aware* that this option may print a _lot_ of lines, > + so there are risks of losing older messages in the log. > + Use this option carefully, maybe worth to setup a > + bigger log buffer with "log_buf_len" along with this. > > panic_on_taint= Bitmask for conditionally calling panic() in add_taint() > Format: [,nousertaint] > diff --git a/kernel/panic.c b/kernel/panic.c > index 41ecf9ab824a..4ae712665f75 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -148,10 +148,13 @@ void nmi_panic(struct pt_regs *regs, const char *msg) > } > EXPORT_SYMBOL(nmi_panic); > > -static void panic_print_sys_info(void) > +static void panic_print_sys_info(bool after_kmsg_dumpers) > { > - if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) > - console_flush_on_panic(CONSOLE_REPLAY_ALL); > + if (after_kmsg_dumpers) { > + if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) > + console_flush_on_panic(CONSOLE_REPLAY_ALL); > + return; > + } > > if (panic_print & PANIC_PRINT_ALL_CPU_BT) > trigger_all_cpu_backtrace(); > @@ -249,7 +252,7 @@ void panic(const char *fmt, ...) > * show some extra information on kernel log if it was set... > */ > if (kexec_crash_loaded()) > - panic_print_sys_info(); > + panic_print_sys_info(false); Patch can'e be applied on the latest code of linus's tree, can you tell which branch your code are based on? > > /* > * If we have crashed and we have a crash kernel loaded let it handle > @@ -283,6 +286,15 @@ void panic(const char *fmt, ...) > */ > atomic_notifier_call_chain(&panic_notifier_list, 0, buf); > > + /* > + * If kexec_crash_loaded() is true and we still reach this point, > + * kernel would double print the information from panic_print; so > + * let's guard against that possibility (it happens if kdump users > + * also set crash_kexec_post_notifiers in the command-line). > + */ > + if (!kexec_crash_loaded()) > + panic_print_sys_info(false); > + > kmsg_dump(KMSG_DUMP_PANIC); > > /* > @@ -313,7 +325,7 @@ void panic(const char *fmt, ...) > debug_locks_off(); > console_flush_on_panic(CONSOLE_FLUSH_PENDING); > > - panic_print_sys_info(); > + panic_print_sys_info(true); > > if (!panic_blink) > panic_blink = no_blink; > -- > 2.34.1 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baoquan He Date: Mon, 17 Jan 2022 11:33:44 +0800 Subject: [PATCH V3] panic: Move panic_print before kmsg dumpers In-Reply-To: <20220114183046.428796-1-gpiccoli@igalia.com> References: <20220114183046.428796-1-gpiccoli@igalia.com> Message-ID: <20220117033344.GA2523@MiWiFi-R3L-srv> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org On 01/14/22 at 03:30pm, Guilherme G. Piccoli wrote: ...... > .../admin-guide/kernel-parameters.txt | 4 ++++ > kernel/panic.c | 22 ++++++++++++++----- > 2 files changed, 21 insertions(+), 5 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index a069d8fe2fee..0f5cbe141bfd 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3727,6 +3727,10 @@ > bit 4: print ftrace buffer > bit 5: print all printk messages in buffer > bit 6: print all CPUs backtrace (if available in the arch) > + *Be aware* that this option may print a _lot_ of lines, > + so there are risks of losing older messages in the log. > + Use this option carefully, maybe worth to setup a > + bigger log buffer with "log_buf_len" along with this. > > panic_on_taint= Bitmask for conditionally calling panic() in add_taint() > Format: [,nousertaint] > diff --git a/kernel/panic.c b/kernel/panic.c > index 41ecf9ab824a..4ae712665f75 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -148,10 +148,13 @@ void nmi_panic(struct pt_regs *regs, const char *msg) > } > EXPORT_SYMBOL(nmi_panic); > > -static void panic_print_sys_info(void) > +static void panic_print_sys_info(bool after_kmsg_dumpers) > { > - if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) > - console_flush_on_panic(CONSOLE_REPLAY_ALL); > + if (after_kmsg_dumpers) { > + if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) > + console_flush_on_panic(CONSOLE_REPLAY_ALL); > + return; > + } > > if (panic_print & PANIC_PRINT_ALL_CPU_BT) > trigger_all_cpu_backtrace(); > @@ -249,7 +252,7 @@ void panic(const char *fmt, ...) > * show some extra information on kernel log if it was set... > */ > if (kexec_crash_loaded()) > - panic_print_sys_info(); > + panic_print_sys_info(false); Patch can'e be applied on the latest code of linus's tree, can you tell which branch your code are based on? > > /* > * If we have crashed and we have a crash kernel loaded let it handle > @@ -283,6 +286,15 @@ void panic(const char *fmt, ...) > */ > atomic_notifier_call_chain(&panic_notifier_list, 0, buf); > > + /* > + * If kexec_crash_loaded() is true and we still reach this point, > + * kernel would double print the information from panic_print; so > + * let's guard against that possibility (it happens if kdump users > + * also set crash_kexec_post_notifiers in the command-line). > + */ > + if (!kexec_crash_loaded()) > + panic_print_sys_info(false); > + > kmsg_dump(KMSG_DUMP_PANIC); > > /* > @@ -313,7 +325,7 @@ void panic(const char *fmt, ...) > debug_locks_off(); > console_flush_on_panic(CONSOLE_FLUSH_PENDING); > > - panic_print_sys_info(); > + panic_print_sys_info(true); > > if (!panic_blink) > panic_blink = no_blink; > -- > 2.34.1 >