• Greg Pearson's avatar
    mm/memblock: fix overlapping allocation when doubling reserved array · 48c3b583
    Greg Pearson authored
    
    
    __alloc_memory_core_early() asks memblock for a range of memory then try
    to reserve it.  If the reserved region array lacks space for the new
    range, memblock_double_array() is called to allocate more space for the
    array.  If memblock is used to allocate memory for the new array it can
    end up using a range that overlaps with the range originally allocated in
    __alloc_memory_core_early(), leading to possible data corruption.
    
    With this patch memblock_double_array() now calls memblock_find_in_range()
    with a narrowed candidate range (in cases where the reserved.regions array
    is being doubled) so any memory allocated will not overlap with the
    original range that was being reserved.  The range is narrowed by passing
    in the starting address and size of the previously allocated range.  Then
    the range above the ending address is searched and if a candidate is not
    found, the range below the starting address is searched.
    
    Signed-off-by: default avatarGreg Pearson <greg.pearson@hp.com>
    Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
    Acked-by: default avatarTejun Heo <tj@kernel.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    48c3b583