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kernel/range.c: fix clean_sort_range() for the case of full array

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clean_sort_range() should return a number of nonempty elements of range
array, but if the array is full clean_sort_range() returns 0.

The problem is that the number of nonempty elements is evaluated by
finding the first empty element of the array.  If there is no such element
it returns an initial value of local variable nr_range that is zero.

The fix is trivial: it changes initial value of nr_range to size of the
array.

The bug can lead to loss of information regarding all ranges, since
typically returned value of clean_sort_range() is considered as an actual
number of ranges in the array after a series of add/subtract operations.

Found by Analytical Verification project of Linux Verification Center
(linuxtesting.org), thanks to Alexander Kolosov.

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Khoroshilov 2010-11-11 14:05:14 -08:00 committed by Linus Torvalds
parent aec0428890
commit 834b40380e
1 changed files with 1 additions and 1 deletions
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2
kernel/range.c
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@ -119,7 +119,7 @@ static int cmp_range(const void *x1, const void *x2)
int clean_sort_range(struct range *range, int az)
{
int i, j, k = az - 1, nr_range = 0;
int i, j, k = az - 1, nr_range = az;
for (i = 0; i < k; i++) {
if (range[i].end)