linux-kernel - Re: [PATCH] [4/4] SLAB: Fix node add timer race in cache

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:	Mon, 15 Feb 2010 17:15:35 +1100
From:	Nick Piggin <npiggin@...e.de>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	penberg@...helsinki.fi, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, haicheng.li@...el.com, rientjes@...gle.com
Subject: Re: [PATCH] [4/4] SLAB: Fix node add timer race in cache_reap

On Thu, Feb 11, 2010 at 09:54:04PM +0100, Andi Kleen wrote:
> 
> cache_reap can run before the node is set up and then reference a NULL 
> l3 list. Check for this explicitely and just continue. The node
> will be eventually set up.

How, may I ask? cpuup_prepare in the hotplug notifier should always
run before start_cpu_timer.

> 
> Signed-off-by: Andi Kleen <ak@...ux.intel.com>
> 
> ---
>  mm/slab.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> Index: linux-2.6.32-memhotadd/mm/slab.c
> ===================================================================
> --- linux-2.6.32-memhotadd.orig/mm/slab.c
> +++ linux-2.6.32-memhotadd/mm/slab.c
> @@ -4093,6 +4093,9 @@ static void cache_reap(struct work_struc
>  		 * we can do some work if the lock was obtained.
>  		 */
>  		l3 = searchp->nodelists[node];
> +		/* Note node yet set up */
> +		if (!l3)
> +			break;
>  
>  		reap_alien(searchp, l3);
>  
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@...ck.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@...ck.org"> email@...ck.org </a>
--
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/