Re: [PATCH v2 0/3] serial: 8250_mxpcie: probe and console fixes

[Crescent Hsieh <crescentcy.hsieh@moxa.com>]

On Tue, Sep 01, 2026 at 12:15:16PM +0800, Linmao Li wrote:
> Three fixes for the Moxa PCIe serial driver, found by reading the code
> that was split out of 8250_pci.c and extended during the 7.3 merge
> window.  That code is in mainline now but has not been in a released
> kernel, so the series is against tty-linus.
> 
> Patch 1 fixes a NULL pointer dereference during probe: the serial core
> calls ->rs485_config() from within serial8250_register_8250_port(),
> before pci_set_drvdata() has published the board.  It takes a board
> without RS232 support and SER_RS485_ENABLED still set once
> uart_get_rs485_mode() has run - on Crescent's ACPI machine the firmware
> node clears that flag, which is why it does not crash there.
> 
> Patch 2 makes removal unregister only the ports that were registered.
> v1 failed the probe instead; as Andy pointed out that is a behavioural
> change, and keeping the ports that do work is what pciserial_init_ports()
> in 8250_pci.c does, so v2 keeps it and restores only the missing count.
> 
> Patch 3 stops set_termios() from dereferencing port->state->port.tty,
> which is NULL when the serial core sets the line up for a console or for
> kgdboc.
> 
> I have no Moxa board here.  Crescent Hsieh tested patch 3 with kgdboc on
> a CP-168EL-A, and looked for patch 1's crash on a CP-134EL-A; the rest is
> compile-tested only, W=1 allmodconfig build of drivers/tty/serial/8250/
> and checkpatch --strict, both clean.

The series looks good to me.

For the series:

Reviewed-by: Crescent Hsieh <crescentcy.hsieh@moxa.com>

The additional pre-existing issues identified by Sashiko are independent
of this series. I will investigate them further and determine the
appropriate follow-up fixes.

--
Thanks,
Crescent Hsieh