• Alexey Khoroshilov's avatar
    kernel/range.c: fix clean_sort_range() for the case of full array · 834b4038
    Alexey Khoroshilov authored
    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: default avatarAlexey 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: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    834b4038
range.c 2.85 KB