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From: Rik van Riel <riel@redhat.com>
To: Andrey Ryabinin <a.ryabinin@samsung.com>,
	peterz@infradead.org, mingo@redhat.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched: core: fix out of bounds read in sched_init_numa()
Date: Fri, 07 Nov 2014 13:49:25 -0500	[thread overview]
Message-ID: <545D1435.90505@redhat.com> (raw)
In-Reply-To: <1415372020-1871-1-git-send-email-a.ryabinin@samsung.com>

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On 11/07/2014 09:53 AM, Andrey Ryabinin wrote:

> Zero 'level' (e.g. on non-NUMA system) causing out of bounds
> access in this line:
> 
> sched_max_numa_distance = sched_domains_numa_distance[level - 1];
> 
> Fix this by exiting from sched_init_numa() earlier.
> 
> Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Fixes:
> 9942f79ba ("sched/numa: Export info needed for NUMA balancing on
> complex topologies")

Reviewed-by: Rik van Riel <riel@redhat.com>

> Another option would be to not call sched_init_numa() if
> nr_node_ids == 1, but I'm not sure that there is no such
> configuration where nr_node_ids > 1 and node_distance(i, j) =
> node_distance(0, 0) for any i and j.

When there is only one node, the distance from the node to itself
will always be equal to node_distance(0, 0)

I am somewhat surprised we go through all of sched_init_numa on
a non-numa system, though :)

- -- 
All rights reversed
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  reply	other threads:[~2014-11-07 18:49 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-07 14:53 Andrey Ryabinin
2014-11-07 18:49 ` Rik van Riel [this message]
2014-11-10  9:36 ` [tip:sched/urgent] sched/numa: Fix " tip-bot for Andrey Ryabinin

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