Re: [PATCH v2 1/1] serial: core: Fix serial_base_match() after fixing controller port name

[Guenter Roeck]

On 8/4/23 21:49, Tony Lindgren wrote:
> * Guenter Roeck <linux@xxxxxxxxxxxx> [230804 21:42]:
> > On Thu, Aug 03, 2023 at 10:10:32AM +0300, Tony Lindgren wrote:
> > > While fixing DEVNAME to be more usable, I broke serial_base_match() as the
> > > ctrl and port prefix for device names seemed unnecessary.
> > >
> > > The prefixes are still needed by serial_base_match() to probe the serial
> > > base controller port, and serial tx is now broken.
> > >
> > > Let's fix the issue by checking against dev->type and drv->name instead
> > > of the prefixes that are no longer in the DEVNAME.
> > >
> > > Fixes: 1ef2c2df1199 ("serial: core: Fix serial core controller port name to show controller id")
> > > Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> > > Closes: https://lore.kernel.org/oe-lkp/202308021529.35b3ad6c-oliver.sang@xxxxxxxxx
> > > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> >
> > With this patch applied, I see the following traceback in the pending-fixes
> > branch.
> >
> > Bisect log attached as well. It actually points to commit d962de6ae51f
> > ("serial: core: Fix serial core port id to not use port->line").
> > Bisect was on mips, but I also see problems on arm, ppc, and sparc.
> > sparc boot tests show the warning message and then stall until aborted
> > (which of course may be a different problem).
>
> Sorry about all the hassles and thanks for testing again.
>
> I too noticed several issues remaining after testing reloading the hardware
> specific serial driver, the issues I saw should be fixed in tty-linus.
>
> > kobject: kobject_add_internal failed for serial8250.0:0.0 with -EEXIST, don't try to register things with the same name in the same directory.
> > serial8250 serial8250.0: unable to register port at index 1 (IO2f8 MEM0 IRQ3): -17
> > sysfs: cannot create duplicate filename '/devices/platform/serial8250.0/serial8250.0:0/serial8250.0:0.0'
>
> The issue above should be fixed with commit:
>
> bbb4abb1bcfb ("serial: 8250: Reinit port_id when adding back serial8250_isa_devs")

No. I tested the tip of tty-linus (v6.5-rc4-9-gdfe2aeb226fd) which includes
above commit, but still see the problem. sparc images also still stall after
the "cannot create duplicate filename" message.
I bisected the sparc problem - it also bisects to commit d962de6ae51f.

The problem affects all mips boot tests, all sparc boot tests, as well as
arm sx1, ppc bamboo and sam460ex emulations. As far as I can see, those
call serial8250_register_8250_port() without calling  serial8250_setup_port()
and thus don't set port_id. I am only testing a few of those, so I strongly
suspect that all similar callers of serial8250_register_8250_port() are
affected (i.e., almost all of them) if they register more than one serial port.

Guenter