From patchwork Thu Feb 1 10:23:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sreenath Vijayan X-Patchwork-Id: 195240 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:2719:b0:106:209c:c626 with SMTP id hl25csp54406dyb; Thu, 1 Feb 2024 02:30:28 -0800 (PST) X-Google-Smtp-Source: AGHT+IGFFZIBmUqOlpgyiFqw4bGs43TdYkiy93tIwQ2WEgF/scgoRa7RDnfkMpSARz8Cy8N4gXAm X-Received: by 2002:a9d:5616:0:b0:6dc:5995:7232 with SMTP id e22-20020a9d5616000000b006dc59957232mr3743984oti.32.1706783428084; Thu, 01 Feb 2024 02:30:28 -0800 (PST) X-Forwarded-Encrypted: i=2; AJvYcCXZdBLCRwKye0qZkDInFm/i50gkxkmVDbZ2R0Ykd++2sCwcf+zl96o6ltdJ9J2kq91PPtuzRXv6626LEscldHbKm+niow== Received: from sv.mirrors.kernel.org (sv.mirrors.kernel.org. [2604:1380:45e3:2400::1]) by mx.google.com with ESMTPS id o25-20020a656159000000b005d8e2f778cesi5206120pgv.525.2024.02.01.02.30.27 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Feb 2024 02:30:28 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-47962-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1; Authentication-Results: mx.google.com; dkim=pass header.i=@Sony.onmicrosoft.com header.s=selector2-Sony-onmicrosoft-com header.b=kgbHVF4f; arc=fail (signature failed); spf=pass (google.com: domain of linux-kernel+bounces-47962-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) smtp.mailfrom="linux-kernel+bounces-47962-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=sony.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sv.mirrors.kernel.org (Postfix) with ESMTPS id C82ED2847CD for ; Thu, 1 Feb 2024 10:27:29 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7374015B97B; Thu, 1 Feb 2024 10:27:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=Sony.onmicrosoft.com header.i=@Sony.onmicrosoft.com header.b="kgbHVF4f" Received: from NAM02-BN1-obe.outbound.protection.outlook.com (mail-bn1nam02on2074.outbound.protection.outlook.com [40.107.212.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 814DA15B11F; Thu, 1 Feb 2024 10:27:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.212.74 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706783237; cv=fail; b=ZXFZWA9iD1EgJiAid7xCA4ITSA3SbEEQzucYr6G948F1lnXKpScnxqGANkNioLoWmYeOWzpPtRVZCOUXcFIw124Ot9SxOq6TuWKsOMiLEdfNdGdBCiXgSucoc4NbAyZ/DCFKqchaCPQqkatXNpyj/FBL9ODLzUp+HZw8H+FXBsw= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706783237; c=relaxed/simple; bh=dl7zBQiz00aLa3C0sBijvnGX2voXiyBV3JaHW0N3+Aw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=soyuoNjjV/gI5aVAhcvw/uqiEAutGR0pyuuo/GWg4klqHiuRHNpcrozVXsSTrOsTpPmPtjnsQzXjBEF2jlifvuKuHYH2sq7cL8DBAi/xYfPQoCLWCprJfj6WteKPr/nNYoGNt3GcRZqHBjRwR1o9RFnxe56qeFdvrha16B3Y7Q8= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sony.com; spf=pass smtp.mailfrom=sony.com; dkim=pass (1024-bit key) header.d=Sony.onmicrosoft.com header.i=@Sony.onmicrosoft.com header.b=kgbHVF4f; arc=fail smtp.client-ip=40.107.212.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sony.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sony.com ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=d3E/hMoxSbTPODboiunyGXb8KREJ5w0jfdD9n1tFFXdKmRnIUJOG5QgHq1GqQkYZ1bAZ6dZqX/ro7LcYFJp6OY4/twrtG1t1OVx6++n8MxwMUbCfTjjhK9DlI4lsppHjUAq51Nf17ceYiC4BSrbMQLIlBPOKyPvBajMDAMnkfmUoTv5qCE34wPmC97x5PnpBZHuvyfjRDD6Rh98dN257Sg0fGXexx3PNKxkR3rjwe7/RJqi8iKqAHKHhrPJLid9BExdVmF5AzpaN1FHQvqsvWzvbWMfBj4+62KumfR6hIzhaoPxRsDw4H8fOx9KuIk/dvz5HpAzjWDeZYD/tEJb39w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=nd6UjDYFfA5A8Fc8/Kuhys73CC0xPe0nBcTw/c6LPAM=; b=g6StuBlHK51LKQkHmgpO9lGbiyPdmHNqQPb68dd6DD8BeQjlTezKctUD0zmvMeRCodcp9a1lshVzVb+QW+1R0CYVTXRdRJyYecEfyDZpNOMJEMy2F+1Zj0MfqIFtY7huu+54I2mFNbe8QTZFE16hE3GvwuX0UcxQF/xEMm+5ajrvneCho+jYChhIXGJ9TFQ4W6GgsG6ed4DrfI2Wb0Stw7OPRgNysynlcE6CmazE/G+0qtBHTM5q1jzNWtGOZ4/IXQezR/AwDzWXOERPvGF9Kdj/XvZoDfegFvXIeaHa+HrzGpGEYmxNb6Wd0A7II2dYasxLWkccj1oGuDiW4CTm8w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=fail (sender ip is 121.100.38.196) smtp.rcpttodomain=vger.kernel.org smtp.mailfrom=sony.com; dmarc=fail (p=none sp=none pct=100) action=none header.from=sony.com; dkim=none (message not signed); arc=none (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Sony.onmicrosoft.com; s=selector2-Sony-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=nd6UjDYFfA5A8Fc8/Kuhys73CC0xPe0nBcTw/c6LPAM=; b=kgbHVF4fMGH0wG0JJGMj9vYkkX5YtgrHs7j89nYPrbM2IxdQc7kGQ3Zy4BNpk+zs0OwmuVhQTEl6Qkmqvo7dJ44wiCRBCnZpdnjmeerP+PBCnxj89/E33ukeFTHlOherRZ+MudV+fwzvwBSxfQPtMjWB3hevkRAvV6BflmBepQs= Received: from DM6PR03CA0079.namprd03.prod.outlook.com (2603:10b6:5:333::12) by CH2PR13MB3654.namprd13.prod.outlook.com (2603:10b6:610:94::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7228.34; Thu, 1 Feb 2024 10:27:12 +0000 Received: from DS1PEPF00017097.namprd05.prod.outlook.com (2603:10b6:5:333:cafe::a3) by DM6PR03CA0079.outlook.office365.com (2603:10b6:5:333::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7249.24 via Frontend Transport; Thu, 1 Feb 2024 10:27:11 +0000 X-MS-Exchange-Authentication-Results: spf=fail (sender IP is 121.100.38.196) smtp.mailfrom=sony.com; dkim=none (message not signed) header.d=none;dmarc=fail action=none header.from=sony.com; Received-SPF: Fail (protection.outlook.com: domain of sony.com does not designate 121.100.38.196 as permitted sender) receiver=protection.outlook.com; client-ip=121.100.38.196; helo=gepdcl07.sg.gdce.sony.com.sg; Received: from gepdcl07.sg.gdce.sony.com.sg (121.100.38.196) by DS1PEPF00017097.mail.protection.outlook.com (10.167.18.101) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7249.19 via Frontend Transport; Thu, 1 Feb 2024 10:27:11 +0000 Received: from gepdcl04.s.gdce.sony.com.sg (SGGDCSE1NS08.sony.com.sg [146.215.123.198]) by gepdcl07.sg.gdce.sony.com.sg (8.14.7/8.14.4) with ESMTP id 411APj0k019868 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 1 Feb 2024 18:26:52 +0800 Received: from mail.sony.com ([43.88.80.246]) by gepdcl04.s.gdce.sony.com.sg (8.14.7/8.14.4) with ESMTP id 411APD0J010487; Thu, 1 Feb 2024 18:25:13 +0800 Received: by mail.sony.com (Postfix, from userid 1000) id 981C220C1C4C; Thu, 1 Feb 2024 15:53:40 +0530 (IST) Date: Thu, 1 Feb 2024 15:53:40 +0530 From: Sreenath Vijayan To: john.ogness@linutronix.de, corbet@lwn.net, gregkh@linuxfoundation.org, jirislaby@kernel.org, pmladek@suse.com Cc: rdunlap@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, taichi.shimoyashiki@sony.com, daniel.palmer@sony.com, anandakumar.balasubramaniam@sony.com, sreenath.vijayan@sony.com Subject: [PATCH v4 1/2] printk: Add function to dump printk buffer directly to consoles Message-ID: <8cb5936021c5811bd03a6bc18300b1384009ac26.1706772349.git.sreenath.vijayan@sony.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS1PEPF00017097:EE_|CH2PR13MB3654:EE_ X-MS-Office365-Filtering-Correlation-Id: 5e083f83-8344-4e76-6574-08dc23105a31 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:121.100.38.196;CTRY:SG;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:gepdcl07.sg.gdce.sony.com.sg;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230031)(4636009)(39860400002)(346002)(376002)(136003)(396003)(230922051799003)(451199024)(1800799012)(64100799003)(186009)(82310400011)(40470700004)(36840700001)(46966006)(40480700001)(40460700003)(44832011)(107886003)(2906002)(6266002)(336012)(5660300002)(2616005)(26005)(70206006)(426003)(42186006)(316002)(8936002)(8676002)(4326008)(47076005)(450100002)(41300700001)(82740400003)(81166007)(36860700001)(478600001)(86362001)(356005)(36756003)(82960400001)(83380400001)(36900700001);DIR:OUT;SFP:1101; X-OriginatorOrg: sony.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Feb 2024 10:27:11.2528 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 5e083f83-8344-4e76-6574-08dc23105a31 X-MS-Exchange-CrossTenant-Id: 66c65d8a-9158-4521-a2d8-664963db48e4 X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=66c65d8a-9158-4521-a2d8-664963db48e4;Ip=[121.100.38.196];Helo=[gepdcl07.sg.gdce.sony.com.sg] X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: TreatMessagesAsInternal-DS1PEPF00017097.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR13MB3654 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1789692139844828132 X-GMAIL-MSGID: 1789692139844828132 It is useful to be able to dump the printk buffer directly to consoles in some situations so as to not flood the buffer. To do this, we reuse the CONSOLE_REPLAY_ALL mode code in console_flush_on_panic() by moving the code to a helper function console_rewind_all(). This is done because console_flush_on_panic() sets console_may_schedule to 0 but this should not be done in our case. Then console_rewind_all() is called from the new function dump_printk_buffer() with console lock held to set the console sequence number to oldest record in the buffer for all consoles. Releasing the console lock will flush the contents of printk buffer to the consoles. Suggested-by: John Ogness Signed-off-by: Sreenath Vijayan Signed-off-by: Shimoyashiki Taichi Reviewed-by: John Ogness --- include/linux/printk.h | 4 +++ kernel/printk/printk.c | 61 +++++++++++++++++++++++++----------------- 2 files changed, 41 insertions(+), 24 deletions(-) diff --git a/include/linux/printk.h b/include/linux/printk.h index 8ef499ab3c1e..861ff5a545ff 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -192,6 +192,7 @@ void show_regs_print_info(const char *log_lvl); extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold; extern asmlinkage void dump_stack(void) __cold; void printk_trigger_flush(void); +void dump_printk_buffer(void); #else static inline __printf(1, 0) int vprintk(const char *s, va_list args) @@ -271,6 +272,9 @@ static inline void dump_stack(void) static inline void printk_trigger_flush(void) { } +static void dump_printk_buffer(void) +{ +} #endif #ifdef CONFIG_SMP diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f2444b581e16..b05ca9f98e53 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3134,6 +3134,32 @@ void console_unblank(void) pr_flush(1000, true); } +static void console_rewind_all(void) +{ + struct console *c; + short flags; + int cookie; + u64 seq; + + seq = prb_first_valid_seq(prb); + + cookie = console_srcu_read_lock(); + for_each_console_srcu(c) { + flags = console_srcu_read_flags(c); + + if (flags & CON_NBCON) { + nbcon_seq_force(c, seq); + } else { + /* + * This is an unsynchronized assignment. On + * panic legacy consoles are only best effort. + */ + c->seq = seq; + } + } + console_srcu_read_unlock(cookie); +} + /** * console_flush_on_panic - flush console content on panic * @mode: flush all messages in buffer or just the pending ones @@ -3162,30 +3188,8 @@ void console_flush_on_panic(enum con_flush_mode mode) */ console_may_schedule = 0; - if (mode == CONSOLE_REPLAY_ALL) { - struct console *c; - short flags; - int cookie; - u64 seq; - - seq = prb_first_valid_seq(prb); - - cookie = console_srcu_read_lock(); - for_each_console_srcu(c) { - flags = console_srcu_read_flags(c); - - if (flags & CON_NBCON) { - nbcon_seq_force(c, seq); - } else { - /* - * This is an unsynchronized assignment. On - * panic legacy consoles are only best effort. - */ - c->seq = seq; - } - } - console_srcu_read_unlock(cookie); - } + if (mode == CONSOLE_REPLAY_ALL) + console_rewind_all(); console_flush_all(false, &next_seq, &handover); } @@ -4259,6 +4263,15 @@ void kmsg_dump_rewind(struct kmsg_dump_iter *iter) } EXPORT_SYMBOL_GPL(kmsg_dump_rewind); +/** + * Dump the printk ring buffer directly to consoles + */ +void dump_printk_buffer(void) +{ + console_lock(); + console_rewind_all(); + console_unlock(); +} #endif #ifdef CONFIG_SMP