linux-kernel - Re: [PATCH v2] mm: Fix slab->page

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: <1337034892.8512.652.camel@edumazet-glaptop>
Date:	Tue, 15 May 2012 00:34:52 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Pravin B Shelar <pshelar@...ira.com>
Cc:	cl@...ux.com, penberg@...nel.org, mpm@...enic.com,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, jesse@...ira.com,
	abhide@...ira.com
Subject: Re: [PATCH v2] mm: Fix slab->page _count corruption.

On Mon, 2012-05-14 at 15:29 -0700, Pravin B Shelar wrote:
> On arches that do not support this_cpu_cmpxchg_double slab_lock is used
> to do atomic cmpxchg() on double word which contains page->_count.
> page count can be changed from get_page() or put_page() without taking
> slab_lock. That corrupts page counter.
> 
> Following patch fixes it by moving page->_count out of cmpxchg_double
> data. So that slub does no change it while updating slub meta-data in
> struct page.

I say again : Page is owned by slub, so get_page() or put_page() is not
allowed ?

How is put_page() going to work with order-1 or order-2 allocations ?

Me very confused by these Nicira patches.


--
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/