From 0c05493341d6f2097f75f0a5dbb7b53a9e8c5f6c Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Fri, 4 Aug 2023 16:15:51 +0300 Subject: [PATCH] serial: 8250: Fix oops for port->pm on uart_change_pm() [ Upstream commit dfe2aeb226fd5e19b0ee795f4f6ed8bc494c1534 ] Unloading a hardware specific 8250 driver can produce error "Unable to handle kernel paging request at virtual address" about ten seconds after unloading the driver. This happens on uart_hangup() calling uart_change_pm(). Turns out commit 04e82793f068 ("serial: 8250: Reinit port->pm on port specific driver unbind") was only a partial fix. If the hardware specific driver has initialized port->pm function, we need to clear port->pm too. Just reinitializing port->ops does not do this. Otherwise serial8250_pm() will call port->pm() instead of serial8250_do_pm(). Fixes: 04e82793f068 ("serial: 8250: Reinit port->pm on port specific driver unbind") Signed-off-by: Tony Lindgren Link: https://lore.kernel.org/r/20230804131553.52927-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/8250/8250_port.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index acf578a..38760bd 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -3281,6 +3281,7 @@ void serial8250_init_port(struct uart_8250_port *up) struct uart_port *port = &up->port; spin_lock_init(&port->lock); + port->pm = NULL; port->ops = &serial8250_pops; port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); -- 2.7.4