Messages in this thread Patch in this message | | | From | Vineet Gupta <> | Subject | [PATCH v2 1/2] memblock: add assertion for zero allocation alignment | Date | Fri, 22 Feb 2013 01:40:21 +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 warn the caller to fix the code.
Tejun suggested that instead of BUG_ON(!align) - which might be ineffective due to pending console init and such, it is better to WARN_ON, and continue the boot with a reasonable default align.
Caller passing @size need not be handled similarly as the subsequent panic will indicate that anyhow.
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 | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/mm/memblock.c b/mm/memblock.c index 1bcd9b9..f3804bd 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -824,6 +824,9 @@ 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); + if (WARN_ON(!align)) + align = __alignof__(long long); + 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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