linux-kernel - Re: [RFC][PATCH v2 22/29] mm/numa: Register information into Kmemdump

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: <e2c031e8-43bd-41e5-9074-c8b1f89e04e6@linaro.org>
Date: Mon, 4 Aug 2025 14:06:11 +0300
From: Eugen Hristev <eugen.hristev@...aro.org>
To: Michal Hocko <mhocko@...e.com>, David Hildenbrand <david@...hat.com>
Cc: linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
 linux-arch@...r.kernel.org, linux-mm@...ck.org, tglx@...utronix.de,
 andersson@...nel.org, pmladek@...e.com,
 linux-arm-kernel@...ts.infradead.org, linux-hardening@...r.kernel.org,
 corbet@....net, mojha@....qualcomm.com, rostedt@...dmis.org,
 jonechou@...gle.com, tudor.ambarus@...aro.org
Subject: Re: [RFC][PATCH v2 22/29] mm/numa: Register information into Kmemdump



On 8/4/25 13:54, Michal Hocko wrote:
> On Wed 30-07-25 16:04:28, David Hildenbrand wrote:
>> On 30.07.25 15:57, Eugen Hristev wrote:
> [...]
>>> Yes, registering after is also an option. Initially this is how I
>>> designed the kmemdump API, I also had in mind to add a flag, but, after
>>> discussing with Thomas Gleixner, he came up with the macro wrapper idea
>>> here:
>>> https://lore.kernel.org/lkml/87ikkzpcup.ffs@tglx/
>>> Do you think we can continue that discussion , or maybe start it here ?
>>
>> Yeah, I don't like that, but I can see how we ended up here.
>>
>> I also don't quite like the idea that we must encode here what to include in
>> a dump and what not ...
>>
>> For the vmcore we construct it at runtime in crash_save_vmcoreinfo_init(),
>> where we e.g., have
>>
>> VMCOREINFO_STRUCT_SIZE(pglist_data);
>>
>> Could we similar have some place where we construct what to dump similarly,
>> just not using the current values, but the memory ranges?
> 
> All those symbols are part of kallsyms, right? Can we just use kallsyms
> infrastructure and a list of symbols to get what we need from there?
> 
> In other words the list of symbols to be completely external to the code
> that is defining them?

Some static symbols are indeed part of kallsyms. But some symbols are
not exported, for example patch 20/29, where printk related symbols are
not to be exported. Another example is with static variables, like in
patch 17/29 , not exported as symbols, but required for the dump.
Dynamic memory regions are not have to also be considered, have a look
for example at patch 23/29 , where dynamically allocated memory needs to
be registered.

Do you think that I should move all kallsyms related symbols annotation
into a separate place and keep it for the static/dynamic regions in place ?

Thanks for looking into my patch,
Eugen