From: Petr Mladek <pmladek@suse.com>
To: John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Marcos Paulo de Souza <mpdesouza@suse.com>,
Chris Down <chris@chrisdown.name>,
Naveen Kumar Chaudhary <naveen.osdev@gmail.com>,
linux-kernel@vger.kernel.org, Petr Mladek <pmladek@suse.com>,
Sashiko <sashiko-bot@kernel.org>
Subject: [PATCH v5 11/16] console/braille: Lock console->setup() call during the registration
Date: Tue, 29 Sep 2026 14:05:41 +0200 [thread overview]
Message-ID: <20260929120546.328616-12-pmladek@suse.com> (raw)
In-Reply-To: <20260929120546.328616-1-pmladek@suse.com>
In braille_register_console(), the console->setup() callback must be
called while holding the console_lock. This prevents a race condition
with a possible active boot console that might be using the same hardware
registers.
See also the commit 801410b26a0e ("serial: Lock console when calling into
driver before registration").
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260423130015.85175-1-pmladek%40suse.com
Suggested-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
---
drivers/accessibility/braille/braille_console.c | 10 +++++-----
include/linux/console.h | 1 +
kernel/printk/printk.c | 2 +-
3 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/accessibility/braille/braille_console.c b/drivers/accessibility/braille/braille_console.c
index 7e6011f9d823..200ca305c6af 100644
--- a/drivers/accessibility/braille/braille_console.c
+++ b/drivers/accessibility/braille/braille_console.c
@@ -389,11 +389,11 @@ int braille_register_console(struct console *console, int index,
console_options = "57600o8";
if (braille_co)
return -ENODEV;
- if (console->setup) {
- ret = console->setup(console, console_options);
- if (ret != 0)
- return ret;
- }
+
+ ret = console_call_setup(console, console_options);
+ if (ret != 0)
+ return ret;
+
console->flags |= CON_ENABLED | CON_BRL;
console->index = index;
braille_co = console;
diff --git a/include/linux/console.h b/include/linux/console.h
index d780f6de303a..11d6b854ee63 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -699,6 +699,7 @@ enum con_flush_mode {
};
extern int add_preferred_console(const char *name, const short idx, char *options);
+extern int console_call_setup(struct console *newcon, char *options);
extern void console_force_preferred_locked(struct console *con);
extern void register_console(struct console *);
extern int unregister_console(struct console *);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 683083405230..f2a602a05614 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3948,7 +3948,7 @@ static int __init keep_bootcon_setup(char *str)
early_param("keep_bootcon", keep_bootcon_setup);
-static int console_call_setup(struct console *newcon, char *options)
+int console_call_setup(struct console *newcon, char *options)
{
int err;
--
2.55.0
next prev parent reply other threads:[~2026-09-29 12:08 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-29 12:05 [PATCH v5 00/16] printk: Clean up preferred console handling Petr Mladek
2026-09-29 12:05 ` [PATCH v5 01/16] printk: Rename struct console_cmdline to preferred_console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 02/16] printk: Rename preferred_console to preferred_dev_console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 03/16] printk: Cleanup _braille_(un)register_console() wrappers Petr Mladek
2026-09-29 12:05 ` [PATCH v5 04/16] printk: Separate code for adding/updating preferred console metadata Petr Mladek
2026-09-29 12:05 ` [PATCH v5 05/16] printk: Prefer the console either via name or devname exclusively Petr Mladek
2026-09-29 12:05 ` [PATCH v5 06/16] printk: Check that index is not defined when a console is preferred via devname Petr Mladek
2026-09-29 12:05 ` [PATCH v5 07/16] printk: Ensure consistent name and devname when updating preferred console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 08/16] printk: Do not quietly ignore adding entry for a preferred console when there is no space Petr Mladek
2026-09-29 12:05 ` [PATCH v5 09/16] printk: Allow to override options via the command line Petr Mladek
2026-09-29 12:05 ` [PATCH v5 10/16] printk: Allow to debug misuse of add_or_update_preferred_console() Petr Mladek
2026-09-29 12:05 ` Petr Mladek [this message]
2026-09-29 12:05 ` [PATCH v5 12/16] printk: Separate code for enabling console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 13/16] printk: Try to register each console as Braille first Petr Mladek
2026-09-29 12:05 ` [PATCH v5 14/16] printk: Do not set Braille console as preferred_console Petr Mladek
2026-09-29 12:05 ` [PATCH v5 15/16] printk: Modify try_enable_default_console() to return error/success Petr Mladek
2026-09-29 12:05 ` [PATCH v5 16/16] printk: Try enable preferred consoles only when there are any Petr Mladek
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