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([2a01:e0a:d5:a000:680e:9bf4:b6a9:959b]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-36791d7a93bsm2401812f8f.81.2024.07.03.09.40.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 03 Jul 2024 09:40:14 -0700 (PDT) Message-ID: <9e7023f4-775c-4371-ade5-1ed860545aaa@redhat.com> Date: Wed, 3 Jul 2024 18:40:12 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] printk: Add a short description string to kmsg_dump() To: Kees Cook , Petr Mladek Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , "Naveen N. Rao" , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Tony Luck , "Guilherme G. Piccoli" , Steven Rostedt , John Ogness , Sergey Senozhatsky , Andrew Morton , Jani Nikula , Greg Kroah-Hartman , Kefeng Wang , Thomas Gleixner , Uros Bizjak , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-hyperv@vger.kernel.org, linux-mtd@lists.infradead.org, linux-hardening@vger.kernel.org References: <20240702122639.248110-1-jfalempe@redhat.com> <202407021326.E75B8EA@keescook> <10ea2ea1-e692-443e-8b48-ce9884e8b942@redhat.com> <202407030926.D5DA9B901D@keescook> Content-Language: en-US, fr From: Jocelyn Falempe In-Reply-To: <202407030926.D5DA9B901D@keescook> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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