Re: [RFC][PATCH] tty: serial: qcom_geni_serial: Drop __init from qcom_geni_console_setup

[Jiri Slaby <jirislaby@kernel.org>]

On 11. 08. 20, 22:02, John Stultz wrote:
> On Tue, Aug 11, 2020 at 10:00 AM Saravana Kannan <saravanak@google.com> wrote:
>>
>> On Mon, Aug 10, 2020 at 7:50 PM John Stultz <john.stultz@linaro.org> wrote:
>>>
>>> When booting with heavily modularized config, the serial console
>>> may not be able to load until after init when modules that
>>> satisfy needed dependencies have time to load.
>>>
>>> Unfortunately, as qcom_geni_console_setup is marked as __init,
>>> the function may have been freed before we get to run it,
>>> causing boot time crashes such as:
>>
>> Btw, I thought non-__init functions calling __init functions would be
>> caught by the build system. Is that not correct? If it's correct, do
>> we know how this gets past that check?
> 
> I think it's because it's indirectly called through a function pointer.

Definitely.

Given there are lots of __init by *_console_setup, I wonder how many
console drivers return EPROBE_DEFER from probe and then register the
console from the same (but deferred) probe like this driver does...

In fact, it doesn't even matter if the probe returns EPROBE_DEFER. The
probe is not marked __init, so the setup shouldn't be either.

thanks,
-- 
js