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driver core: numa: fix BUILD_BUG_ON for node_read_distance

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node_read_distance() has a BUILD_BUG_ON() to prevent buffer overruns when
the number of nodes printed will exceed the buffer length.

Each node only needs four chars: three for distance (maximum distance is
255) and one for a seperating space or a trailing newline.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
David Rientjes 2010-03-10 14:50:21 -08:00 committed by Greg Kroah-Hartman
parent f0eae0ed3b
commit 12ee3c0a0a
1 changed files with 5 additions and 2 deletions
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7
drivers/base/node.c
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@ -165,8 +165,11 @@ static ssize_t node_read_distance(struct sys_device * dev,
int len = 0;
int i;
/* buf currently PAGE_SIZE, need ~4 chars per node */
BUILD_BUG_ON(MAX_NUMNODES*4 > PAGE_SIZE/2);
/*
* buf is currently PAGE_SIZE in length and each node needs 4 chars
* at the most (distance + space or newline).
*/
BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
for_each_online_node(i)
len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));