linux-kernel - Re: [2.6.35-rc6 patch] increase kmemleak robustness at boot

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]

Date:	Thu, 29 Jul 2010 21:39:31 +0100
From:	Catalin Marinas <catalin.marinas@...il.com>
To:	Pekka Enberg <penberg@...helsinki.fi>
Cc:	Daniel J Blueman <daniel.blueman@...il.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [2.6.35-rc6 patch] increase kmemleak robustness at boot

On 29 July 2010 19:50, Pekka Enberg <penberg@...helsinki.fi> wrote:
> On Thu, Jul 29, 2010 at 9:03 PM, Daniel J Blueman
> <daniel.blueman@...il.com> wrote:
>>> If it's just kmemleak_init() we're talking about, slab caches are up at that
>>> point so you can just use kmalloc().
>>
>> The slab allocator isn't up at this point. With
>> CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE set to 16K elements, an extra 3MB
>> of __initdata memory is used, but freed afterwards, and it works
>> great.
>
> Right. I guess the required earlylog buffer size would be smaller if
> we initialized kmemleak earlier. Can we do that in mm_init() after
> kmem_cache_init()?

Kmemleak uses kmem_cache_alloc() internally so we could initialise it
as soon as kmem_cache_init() was called. But it's really strange the
amount of early allocations that Daniel is getting. I've been happy so
far with 400, usually with standard Ubuntu-like configs and some
debugging turned on. Any idea what's causing these allocations?

-- 
Catalin
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/