On Thu, Apr 13, 2023 at 10:03:41AM +0300, Tony Lindgren wrote: > When we unbind a serial port hardware specific 8250 driver, the generic > serial8250 driver takes over the port. After that we see an oops about 10 > seconds later. This can produce the following at least on some TI SoCs: > > Unhandled fault: imprecise external abort (0x1406) > Internal error: : 1406 [#1] SMP ARM > > Turns out that we may still have the serial port hardware specific driver > port->pm in use, and serial8250_pm() tries to call it after the port > specific driver is gone: > > serial8250_pm [8250_base] from uart_change_pm+0x54/0x8c [serial_base] > uart_change_pm [serial_base] from uart_hangup+0x154/0x198 [serial_base] > uart_hangup [serial_base] from __tty_hangup.part.0+0x328/0x37c > __tty_hangup.part.0 from disassociate_ctty+0x154/0x20c > disassociate_ctty from do_exit+0x744/0xaac > do_exit from do_group_exit+0x40/0x8c > do_group_exit from __wake_up_parent+0x0/0x1c > > Let's fix the issue by clearing port->pm in serial8250_unregister_port(). Sounds to me like a fix that needs a Fixes tag. Code wise LGTM, Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> > --- > drivers/tty/serial/8250/8250_core.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c > --- a/drivers/tty/serial/8250/8250_core.c > +++ b/drivers/tty/serial/8250/8250_core.c > @@ -1157,6 +1157,7 @@ void serial8250_unregister_port(int line) > uart->port.flags &= ~UPF_BOOT_AUTOCONF; > uart->port.type = PORT_UNKNOWN; > uart->port.dev = &serial8250_isa_devs->dev; > + uart->port.pm = NULL; > uart->capabilities = 0; > serial8250_apply_quirks(uart); > uart_add_one_port(&serial8250_reg, &uart->port); > -- > 2.40.0 -- With Best Regards, Andy Shevchenko
