Re: [PATCH] gpio: xgs-iproc: Fix section mismatch on device tree match table

[Guillaume Tucker <guillaume.tucker@xxxxxxxxxxxxx>]

On 06/11/2019 19:49, Chris Packham wrote:
> (adding Guillamume),
> 
> On Wed, 2019-11-06 at 07:08 +0000, Yoshihiro Shimoda wrote:
>> Hi Mark,
>>
>>> From: Mark Brown, Sent: Tuesday, November 5, 2019 9:49 PM
>>>
>>> The table of devicetree identifiers is annotated as __initconst
>>> indicating that it can be discarded after kernel boot but it is
>>> referenced from the driver struct which has no init annotation leading
>>> to a linker warning:
>>>
>>> WARNING: vmlinux.o(.data+0x82d58): Section mismatch in reference from the variable bcm_iproc_gpio_driver to the
>>> variable .init.rodata:bcm_iproc_gpio_of_match
>>> The variable bcm_iproc_gpio_driver references
>>> the variable __initconst bcm_iproc_gpio_of_match
>>>
>>> Since drivers can be probed after init the lack of annotation on the
>>> driver struct is correct so remove the annotation from the match table.
>>>
>>> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
>>
>> Thank you for the patch! Without this patch, I had encountered another
>> issue which my environment caused a panic when I tried to install a usb host
>> driver after booted [1]. But, I could resolved the issue after
>> I applied this patch. Also, I confirmed this patch could resolved the warning.
>>
>> So,
>> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
>> Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
>>
>> Best regards,
>> Yoshihiro Shimoda
>>
>> ---
>> [1]
>> [  146.541188] Unable to handle kernel paging request at virtual address ffff800011f73540
>> [  146.549099] Mem abort info:
>> [  146.551885]   ESR = 0x96000007
>> [  146.554934]   EC = 0x25: DABT (current EL), IL = 32 bits
>> [  146.560238]   SET = 0, FnV = 0
>> [  146.563284]   EA = 0, S1PTW = 0
>> [  146.566416] Data abort info:
>> [  146.569289]   ISV = 0, ISS = 0x00000007
>> [  146.573117]   CM = 0, WnR = 0
>> [  146.576078] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000049e4a000
>> [  146.582770] [ffff800011f73540] pgd=000000077ffff003, pud=000000077fffe003, pmd=000000077fffb003, pte=0000000000000000
>> [  146.593375] Internal error: Oops: 96000007 [#1] PREEMPT SMP
>> [  146.598944] CPU: 0 PID: 106 Comm: kworker/0:1 Not tainted 5.4.0-rc6-next-20191105 #87
>> [  146.606766] Hardware name: Renesas Salvator-X 2nd version board based on r8a7795 ES2.0+ (DT)
>> [  146.615209] Workqueue: events deferred_probe_work_func
>> [  146.620341] pstate: a0000085 (NzCv daIf -PAN -UAO)
>> [  146.625132] pc : __of_match_node.part.4+0x3c/0x78
>> [  146.629830] lr : of_match_node+0x3c/0x70
>> ...
>> ---
>>
>>
>> So,
> 
> I guess that kernelci failure[1] wasn't bogus after all. Sorry again
> for the hassle. And Mark, Yoshihiro thanks for the fix and test.

Thanks for the follow-up, I'll re-enable bisections in
lab-theobroma-systems then.

It's actually pretty hard to get false positives from this
automated bisection thanks to some checks run on the commit
found, to verify it does cause a boot failure and also verify
that when reverted the problem goes away.  This was a good
example :)

Guillaume

> [1] - 
> https://lore.kernel.org/lkml/5dbb2acf.1c69fb81.54ce2.2f48@xxxxxxxxxxxxx/
> 
>>
>>
>> Best regards,
>> Yoshihiro Shimoda
>>
>>
>>> ---
>>>  drivers/gpio/gpio-xgs-iproc.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpio/gpio-xgs-iproc.c b/drivers/gpio/gpio-xgs-iproc.c
>>> index a3fdd95cc9e6..bb183f584d92 100644
>>> --- a/drivers/gpio/gpio-xgs-iproc.c
>>> +++ b/drivers/gpio/gpio-xgs-iproc.c
>>> @@ -299,7 +299,7 @@ static int __exit iproc_gpio_remove(struct platform_device *pdev)
>>>  	return 0;
>>>  }
>>>
>>> -static const struct of_device_id bcm_iproc_gpio_of_match[] __initconst = {
>>> +static const struct of_device_id bcm_iproc_gpio_of_match[] = {
>>>  	{ .compatible = "brcm,iproc-gpio-cca" },
>>>  	{}
>>>  };
>>> --
>>> 2.20.1
>>
>>
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