[+Cc: hpa] On Thu, Feb 21, 2013 at 10:39 AM, Vineet Gupta <[email protected]> wrote: > 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.
should we just make align to 1 instead of 0 ? or BUG_ON(!align) instead? > > 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/ -- 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/
