[PATCH 1/2] tty: serial: remove __init on pl011 console ops

[Linus Walleij]

On Wed, Feb 6, 2013 at 1:31 PM, Haojian Zhuang
<haojian.zhuang at linaro.org> wrote:

CC Grant on this issue...

> On 6 February 2013 19:52, Russell King - ARM Linux
> <linux at arm.linux.org.uk> wrote:
>> On Wed, Feb 06, 2013 at 07:47:14PM +0800, Haojian Zhuang wrote:
>>> If uart driver is probed defer, console_setup will be called later
>>> after __init && __initdata sections destroyed. And amba_console isn't
>>> defined in __init or __initdata section. So we needn't define
>>> pl011_console_setup() && pl011_console_get_options() in __init section.
>>
>> It sounds like there's a deeper problem here - if this driver being
>> deferred, why isn't it being retried after the pinctrl stuff gets
>> its driver registered?
>>
>> We've had bugs in this deferred probing before, I wouldn't be surprised
>> if there's more... and we should not be "fixing" drivers because of bugs
>> elsewhere.
>
> It retried if driver is being deferred. But those console setup
> functions are released
> since they're declared in __init section.
>
> rest_init()
>    --> creates kernel_init thread that could free __init section memory
>
> deferred_probe_initicall() creates a workqueue that is used to retry
> deferred probe
> function.
>
> I think that these two threads are competing.

Now that is the *real* problem. The __init sections surely should
not be discarded until *after* all deferred probes are complete
and the deferral workqueue terminates.

How about writing a patch to fix that instead? (If possible...)

Yours,
Linus Walleij