linux-kernel - Re: [RFC PATCH 1/5] mm, slub: extend slub

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] [day] [month] [year] [list]

Message-ID: <a9310f8b-ef99-089a-4932-e15cbf09def4@suse.cz>
Date:   Mon, 8 Jun 2020 18:58:55 +0200
From:   Vlastimil Babka <vbabka@...e.cz>
To:     Kees Cook <keescook@...omium.org>
Cc:     Christoph Lameter <cl@...ux.com>,
        Pekka Enberg <penberg@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, kernel-team@...roid.com,
        vinmenon@...eaurora.org, Matthew Garrett <mjg59@...gle.com>,
        Jann Horn <jannh@...gle.com>,
        Vijayanand Jitta <vjitta@...eaurora.org>
Subject: Re: [RFC PATCH 1/5] mm, slub: extend slub_debug syntax for multiple
 blocks


On 6/5/20 11:06 PM, Kees Cook wrote:
>> @@ -83,6 +88,18 @@ in low memory situations or if there's high fragmentation of memory.  To
>>  
>>  	slub_debug=O
>>  
>> +You can apply different options to different list of slab names, using blocks
>> +of options. This will enable red zoning for dentry and user tracking for
>> +kmalloc. All other slabs will not get any debugging enabled::
>> +
>> +	slub_debug=Z,dentry;U,kmalloc-*
>> +
>> +You can also enable options (e.g. sanity checks and poisoning) for all caches
>> +except some that are deemed too performance critical and don't need to be
>> +debugged::
> 
> Just for more clarity, how about:
> 
>  ... debugged by starting the list with "-" (to mean "all except the
> following")::

Hmm, "-" is not exactly "all except the following", but "no debugging", as
explained in the list of debug options earlier in the file.

So I'm updating it to this:

You can also enable options (e.g. sanity checks and poisoning) for all caches
except some that are deemed too performance critical and don't need to be
debugged by specifying global debug options followed by a list of slab names
with "-" as options::

        slub_debug=FZ;-,zs_handle,zspage


>> +
>> +	slub_debug=FZ;-,zs_handle,zspage
>> +
>>  In case you forgot to enable debugging on the kernel command line: It is
>>  possible to enable debugging manually when the kernel is up. Look at the
>>  contents of::
> 
> Everything else looks great; very nice! :)
> 
> Reviewed-by: Kees Cook <keescook@...omium.org>
 
Thanks!