linux-kernel - Re: [PATCH v2] printk: Add a short description string to kmsg

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <9e7023f4-775c-4371-ade5-1ed860545aaa@redhat.com>
Date: Wed, 3 Jul 2024 18:40:12 +0200
From: Jocelyn Falempe <jfalempe@...hat.com>
To: Kees Cook <kees@...nel.org>, Petr Mladek <pmladek@...e.com>
Cc: Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin
 <npiggin@...il.com>, Christophe Leroy <christophe.leroy@...roup.eu>,
 "Naveen N. Rao" <naveen.n.rao@...ux.ibm.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
 "K. Y. Srinivasan" <kys@...rosoft.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>,
 Dexuan Cui <decui@...rosoft.com>, Miquel Raynal <miquel.raynal@...tlin.com>,
 Richard Weinberger <richard@....at>, Vignesh Raghavendra <vigneshr@...com>,
 Tony Luck <tony.luck@...el.com>, "Guilherme G. Piccoli"
 <gpiccoli@...lia.com>, Steven Rostedt <rostedt@...dmis.org>,
 John Ogness <john.ogness@...utronix.de>,
 Sergey Senozhatsky <senozhatsky@...omium.org>,
 Andrew Morton <akpm@...ux-foundation.org>,
 Jani Nikula <jani.nikula@...el.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Kefeng Wang <wangkefeng.wang@...wei.com>,
 Thomas Gleixner <tglx@...utronix.de>, Uros Bizjak <ubizjak@...il.com>,
 linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, linux-hyperv@...r.kernel.org,
 linux-mtd@...ts.infradead.org, linux-hardening@...r.kernel.org
Subject: Re: [PATCH v2] printk: Add a short description string to kmsg_dump()

On 03/07/2024 18:27, Kees Cook wrote:
> On Wed, Jul 03, 2024 at 10:22:11AM +0200, Petr Mladek wrote:
>> On Wed 2024-07-03 09:57:26, Jocelyn Falempe wrote:
>>>
>>>
>>> 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 ?
>>
>> Andrew usually takes patches against kernel/panic.c.
>>
>> Or you could take it via the DRM tree, especially if you already have the code
>> using the string.

If it's not taken in Andrew's tree next week, I will see if I can push 
it to the drm-misc tree. I think there is a very low chance of conflicts.

>>
>> Also I could take it via the printk tree. The only complication is
>> that I am going to be away the following two weeks and would come
>> back in the middle of the merge window. I do not expect much problems
>> with this change but...
> 
> If DRM doesn't want to carry it, I can put it in through the pstore
> tree. Let me know! :)
> 

Thanks for the proposition, I will see how it goes, it would be nice to 
have it in time for the v6.11 merge window.

Best regards,

-- 

Jocelyn