Messages in this thread Patch in this message | | | From | Vineet Gupta <> | Subject | [PATCH 1/2] memblock: add assertion for zero allocation size | Date | Fri, 22 Feb 2013 00:09:21 +0530 |
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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 <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
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