Messages in this thread | | | Date | Thu, 21 Feb 2013 11:27:16 -0800 | Subject | Re: [PATCH 1/2] memblock: add assertion for zero allocation size | From | Yinghai Lu <> |
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[+Cc: hpa]
On Thu, Feb 21, 2013 at 10:39 AM, Vineet Gupta <Vineet.Gupta1@synopsys.com> 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 <vgupta@synopsys.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Tejun Heo <tj@kernel.org> > Cc: Yinghai Lu <yinghai@kernel.org> > Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > 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 majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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