linux-kernel - Re: [PATCH] mm: slub: Panic if the object corruption is checked.

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 for Android: free password hash cracker in your pocket

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

Message-ID: <712ff549-5ef2-418f-a0a2-8a3da04f03fd@suse.cz>
Date: Tue, 21 Jan 2025 11:28:37 +0100
From: Vlastimil Babka <vbabka@...e.cz>
To: Hyesoo Yu <hyesoo.yu@...sung.com>, Hyeonggon Yoo <hyeonggon.yoo@...com>
Cc: Hyeonggon Yoo <42.hyeyoo@...il.com>, kernel_team@...ynix.com,
 "janghyuck.kim@...sung.com" <janghyuck.kim@...sung.com>,
 Andrew Morton <akpm@...ux-foundation.org>, Jonathan Corbet <corbet@....net>,
 Christoph Lameter <cl@...ux.com>, Pekka Enberg <penberg@...nel.org>,
 David Rientjes <rientjes@...gle.com>, Joonsoo Kim <iamjoonsoo.kim@....com>,
 Roman Gushchin <roman.gushchin@...ux.dev>,
 "linux-mm@...ck.org" <linux-mm@...ck.org>,
 "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm: slub: Panic if the object corruption is checked.

On 1/21/25 3:32 AM, Hyesoo Yu wrote:
> On Tue, Jan 21, 2025 at 10:48:08AM +0900, Hyeonggon Yoo wrote:
>>
>>
>> On 1/21/2025 9:54 AM, Hyesoo Yu wrote:
>>> On Tue, Jan 21, 2025 at 12:41:01AM +0900, Hyeonggon Yoo wrote:
>>>> On Mon, Jan 20, 2025 at 5:30 PM Hyesoo Yu <hyesoo.yu@...sung.com> wrote:
>>>
>>> Thanks for response.
>>>
>>> Using warn() instead of panic, is a great idea.
>>> Thanks for pointing out what I missed.
>>
>> Just for clarification, I think changing the common error reporting
>> logic (like, slab_bug()) to use WARN() will be preferable to inserting
>> new WARN()s at random points, which is what this patch does now.
>>
>> Best,
>> Hyeonggon
>>
> 
> Thanks you for clarification.
> 
> Actually, I considered adding BUG_ON() to slab_bug. However if we add BUG_ON() to slab_bug,
> it will prevent many meaningful error log from being printed subsequently.
> As you know, slab_bug is the log that usually is printed at the biginning of a bug
> in the slab. As a result, it would be difficult to figure out the problems based on
> the logs during our large-scale test-bed.
> 
> Similary, even if I use WARN() in slab_bug, we won't be able to obtain the logs
> when panic_on_warn is enabled. I don't think it is useful to include WARN in slab_bug.
> 
> Instead, I will implement a solution where WARN is only used in slab_fix before
> slab object is restored. If I add it to slab_fix, I think warning is suppressed on
> kunit test by slab_add_kunit_errors handling.

Right, makes sense to only do the WARN() after printing the debugging
logs. Thanks.

> Thanks,
> Regards.
> 
>