This is a note to let you know that I've just added the patch titled
serial: 8250: Fix oops for port->pm on uart_change_pm()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-8250-fix-oops-for-port-pm-on-uart_change_pm.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8b19e3508c6c8fdc1ba119e4df55c4a89bef64ce
Author: Tony Lindgren <tony@xxxxxxxxxxx>
Date: Fri Aug 4 16:15:51 2023 +0300
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 <tony@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230804131553.52927-1-tony@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index f49f3b017206c..4770513944d43 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3135,6 +3135,7 @@ 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;
up->cur_iotype = 0xFF;
