Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752966AbdCBNPf (ORCPT ); Thu, 2 Mar 2017 08:15:35 -0500 Received: from mail-lf0-f51.google.com ([209.85.215.51]:33523 "EHLO mail-lf0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752894AbdCBNP3 (ORCPT ); Thu, 2 Mar 2017 08:15:29 -0500 From: Aleksey Makarov To: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Aleksey Makarov , Sudeep Holla , Greg Kroah-Hartman , Peter Hurley , Jiri Slaby , Robin Murphy , Steven Rostedt , "Nair, Jayachandran" , Petr Mladek , Sergey Senozhatsky Subject: [PATCH v2 3/3] printk: fix double printing with earlycon Date: Thu, 2 Mar 2017 16:11:34 +0300 Message-Id: <20170302131153.22733-4-aleksey.makarov@linaro.org> X-Mailer: git-send-email 2.11.1 In-Reply-To: <20170302131153.22733-1-aleksey.makarov@linaro.org> References: <20170302131153.22733-1-aleksey.makarov@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3538 Lines: 106 If a console was specified by ACPI SPCR table _and_ command line parameters like "console=ttyAMA0" _and_ "earlycon" were specified, then log messages appear twice. The root cause is that the code traverses the list of specified consoles (the `console_cmdline` array) and stops at the first match. But it may happen that the same console is referred by the elements of this array twice: pl011,mmio,0x87e024000000,115200 -- from SPCR ttyAMA0 -- from command line but in this case `preferred_console` points to the second entry and the flag CON_CONSDEV is not set, so bootconsole is not deregistered. To fix that, match the console against the `console_cmdline` entry pointed by `preferred_console` instead of the first match. Signed-off-by: Aleksey Makarov --- kernel/printk/printk.c | 49 ++++++++++++++++++++++++++++++++++--------------- 1 file changed, 34 insertions(+), 15 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index ed2a9b31f214..ad35011f8374 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2380,6 +2380,24 @@ static int __init keep_bootcon_setup(char *str) early_param("keep_bootcon", keep_bootcon_setup); +static int match_console(struct console *newcon, struct console_cmdline *c) +{ + if (!newcon->match || + newcon->match(newcon, c->name, c->index, c->options) != 0) { + /* default matching */ + BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name)); + if (strcmp(c->name, newcon->name) != 0) + return -ENODEV; + if (newcon->index >= 0 && + newcon->index != c->index) + return -ENODEV; + if (newcon->index < 0) + newcon->index = c->index; + } + + return 0; +} + /* * The console driver calls this routine during kernel initialization * to register the console printing procedure with printk() and to @@ -2460,17 +2478,9 @@ void register_console(struct console *newcon) for (i = 0, c = console_cmdline; i < MAX_CMDLINECONSOLES && c->name[0]; i++, c++) { - if (!newcon->match || - newcon->match(newcon, c->name, c->index, c->options) != 0) { - /* default matching */ - BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name)); - if (strcmp(c->name, newcon->name) != 0) - continue; - if (newcon->index >= 0 && - newcon->index != c->index) - continue; - if (newcon->index < 0) - newcon->index = c->index; + if (match_console(newcon, c)) { + continue; + } else { if (_braille_register_console(newcon, c)) return; @@ -2481,10 +2491,6 @@ void register_console(struct console *newcon) } newcon->flags |= CON_ENABLED; - if (i == preferred_console) { - newcon->flags |= CON_CONSDEV; - has_preferred = true; - } break; } @@ -2492,6 +2498,19 @@ void register_console(struct console *newcon) return; /* + * Check if this console was set as preferred by command line parameters + * or by call to add_preferred_console(). + * There may be several entries in the console_cmdline array referring + * to the same console so we can not just use the first match. Instead + * check the entry pointed by preferred_console explicitly. + */ + if (preferred_console >= 0 && + match_console(newcon, console_cmdline + preferred_console) == 0) { + newcon->flags |= CON_CONSDEV; + has_preferred = true; + } + + /* * If we have a bootconsole, and are switching to a real console, * don't print everything out again, since when the boot console, and * the real console are the same physical device, it's annoying to -- 2.11.1