5.4-stable review patch. If anyone has any objections, please let me know.
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From: Tony Lindgren tony@atomide.com
[ 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@atomide.com Link: https://lore.kernel.org/r/20230804131553.52927-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 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;