| Message ID | 20230804131553.52927-1-tony@atomide.com |
|---|---|
| State | New |
| Headers | show |
| Series | serial: 8250: Fix oops for port->pm on uart_change_pm() | expand |
On Fri, Aug 04, 2023 at 04:15:51PM +0300, Tony Lindgren wrote: > 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(). Oh, good catch! Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
On Aug 04, 2023 at 16:15:51 +0300, Tony Lindgren wrote: > 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(). Thanks for catching and fixing this! > > Fixes: 04e82793f068 ("serial: 8250: Reinit port->pm on port specific driver unbind") > Signed-off-by: Tony Lindgren <tony@atomide.com> > --- > 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 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -3278,6 +3278,7 @@ void serial8250_init_port(struct uart_8250_port *up) > > spin_lock_init(&port->lock); > port->ctrl_id = 0; > + port->pm = NULL; Reviewed-by: Dhruva Gole <d-gole@ti.com> > port->ops = &serial8250_pops; > port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); > > -- > 2.41.0
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -3278,6 +3278,7 @@ void serial8250_init_port(struct uart_8250_port *up) spin_lock_init(&port->lock); port->ctrl_id = 0; + port->pm = NULL; port->ops = &serial8250_pops; port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
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> --- drivers/tty/serial/8250/8250_port.c | 1 + 1 file changed, 1 insertion(+)