From 7e537af997748ea7a8df3f2b234a877ea9ef7791 Mon Sep 17 00:00:00 2001
From: John Ogness <john.ogness@linutronix.de>
Date: Wed, 16 Nov 2022 17:27:47 +0106
Subject: [PATCH] tty: serial: kgdboc: use srcu console list iterator
Use srcu console list iteration for safe console list traversal.
Note that this is a preparatory change for when console_lock no
longer provides synchronization for the console list.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-36-john.ogness@linutronix.de
---
drivers/tty/serial/kgdboc.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index 5be381003e585..c6df9ef340990 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -451,6 +451,7 @@ static void kgdboc_earlycon_pre_exp_handler(void)
{
struct console *con;
static bool already_warned;
+ int cookie;
if (already_warned)
return;
@@ -463,9 +464,14 @@ static void kgdboc_earlycon_pre_exp_handler(void)
* serial drivers might be OK with this, print a warning once per
* boot if we detect this case.
*/
- for_each_console(con)
+ cookie = console_srcu_read_lock();
+ for_each_console_srcu(con) {
if (con == kgdboc_earlycon_io_ops.cons)
- return;
+ break;
+ }
+ console_srcu_read_unlock(cookie);
+ if (con)
+ return;
already_warned = true;
pr_warn("kgdboc_earlycon is still using bootconsole\n");