[PATCH v2] printk: Add a short description string to kmsg_dump()

[Jocelyn Falempe]

On 02/07/2024 22:29, Kees Cook wrote:
> On Tue, Jul 02, 2024 at 02:26:04PM +0200, Jocelyn Falempe wrote:
>> kmsg_dump doesn't forward the panic reason string to the kmsg_dumper
>> callback.
>> This patch adds a new struct kmsg_dump_detail, that will hold the
>> reason and description, and pass it to the dump() callback.
> 
> Thanks! I like this much better. :)
> 
>>
>> To avoid updating all kmsg_dump() call, it adds a kmsg_dump_desc()
>> function and a macro for backward compatibility.
>>
>> I've written this for drm_panic, but it can be useful for other
>> kmsg_dumper.
>> It allows to see the panic reason, like "sysrq triggered crash"
>> or "VFS: Unable to mount root fs on xxxx" on the drm panic screen.
>>
>> v2:
>>   * Use a struct kmsg_dump_detail to hold the reason and description
>>     pointer, for more flexibility if we want to add other parameters.
>>     (Kees Cook)
>>   * Fix powerpc/nvram_64 build, as I didn't update the forward
>>     declaration of oops_to_nvram()
> 
> The versioning history commonly goes after the "---".

ok, I was not aware of this.
> 
>> [...]
>> diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
>> index 906521c2329c..65f5a47727bc 100644
>> --- a/include/linux/kmsg_dump.h
>> +++ b/include/linux/kmsg_dump.h
>> @@ -39,6 +39,17 @@ struct kmsg_dump_iter {
>>   	u64	next_seq;
>>   };
>>   
>> +/**
>> + *struct kmsg_dump_detail - kernel crash detail
> 
> Is kern-doc happy with this? I think there is supposed to be a space
> between the "*" and the first word:
> 
>   /**
>    * struct kmsg...
> 
> 
Good catch, yes there is a space missing.

I just checked with "make htmldocs", and in fact 
include/linux/kmsg_dump.h is not indexed for kernel documentation.
And you can't find the definition of struct kmsg_dumper in the online doc.
https://www.kernel.org/doc/html/latest/search.html?q=kmsg_dumper

> Otherwise looks good to me!
> 

Thanks.

As this patch touches different subsystems, do you know on which tree it 
should land ?

-- 

Jocelyn