This came to light when calling memblock allocator from arc port (for copying flattended DT). If a "0" alignment is passed, the allocator round_up() call incorrectly rounds up the size to 0.
round_up(num, alignto) => ((num - 1) | (alignto -1)) + 1 While the obvious allocation failure causes kernel to panic, it is better to BUG_ON() if effective size for allocation (as passed by caller and/or computed after alignemtn rounding) is zero. Signed-off-by: Vineet Gupta <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Yinghai Lu <[email protected]> Cc: Wanpeng Li <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: [email protected] Cc: [email protected] --- mm/memblock.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/mm/memblock.c b/mm/memblock.c index 1bcd9b9..32b36d0 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -824,6 +824,8 @@ static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size, /* align @size to avoid excessive fragmentation on reserved array */ size = round_up(size, align); + BUG_ON(!size); + found = memblock_find_in_range_node(0, max_addr, size, align, nid); if (found && !memblock_reserve(found, size)) return found; -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
