From 7e537af997748ea7a8df3f2b234a877ea9ef7791 Mon Sep 17 00:00:00 2001 From: John Ogness 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 Reviewed-by: Petr Mladek Reviewed-by: Douglas Anderson Signed-off-by: Petr Mladek 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 5be381003e58..c6df9ef34099 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");