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[195.250.132.146]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a00d453badsm47404935e9.2.2026.09.29.05.09.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Sep 2026 05:09:02 -0700 (PDT) From: Petr Mladek To: John Ogness Cc: Sergey Senozhatsky , Steven Rostedt , Marcos Paulo de Souza , Chris Down , Naveen Kumar Chaudhary , linux-kernel@vger.kernel.org, Petr Mladek Subject: [PATCH v5 16/16] printk: Try enable preferred consoles only when there are any Date: Tue, 29 Sep 2026 14:05:46 +0200 Message-ID: <20260929120546.328616-17-pmladek@suse.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260929120546.328616-1-pmladek@suse.com> References: <20260929120546.328616-1-pmladek@suse.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit try_enable_preferred_console() used to be always called because it had several hidden effects, namely: - returned success when a console was pre-enabled using CON_ENABLED flag. - enabled Braille consoles which were ignored by "preferred_dev_console" because they were not associated with /dev/console. - returned success when a console was enabled by default because try_enable_default_console() did not return success. The first two hidden effects were removed in previous patches. The already fixed handling of pre-enabled consoles actually helps even the 3rd case. try_enable_default_console() sets CON_ENABLED flag on success and is later handled as pre-enabled. Prevent any future hidden effects and call try_enable_preferred_console() only when some console is preferred. No behavior change. Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 1eb749da9e24..06c49042dd8f 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -4085,7 +4085,7 @@ static int try_enable_default_console(struct console *newcon) static int try_enable_console(struct console *newcon) { - int err; + int err = -ENOENT; /* * First, try to enable the console driver as a Braille console. @@ -4124,16 +4124,24 @@ static int try_enable_console(struct console *newcon) if (err != -ENOENT) return err; } + } else { + /* See if this console matches one we selected on the command line */ + err = try_enable_preferred_console(newcon, true); + if (err != -ENOENT) + return err; + + /* If not, try to match against the platform default(s) */ + err = try_enable_preferred_console(newcon, false); + if (err != -ENOENT) + return err; } - /* See if this console matches one we selected on the command line */ - err = try_enable_preferred_console(newcon, true); - if (err != -ENOENT) - return err; - - /* If not, try to match against the platform default(s) */ - err = try_enable_preferred_console(newcon, false); - if (err != -ENOENT) + /* + * Make sure that pre-enabled consoles won't get registered when + * something went wrong. This is just a paranoid check that all + * branches above returned on error. + */ + if (WARN_ON(err != -ENOENT)) return err; /* -- 2.55.0