From 94f3d3afb65f27d4e7b8251e323c6418982cb9c7 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Mon, 29 Apr 2013 15:06:15 -0700 Subject: [PATCH] memblock: add assertion for zero allocation alignment 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 Cc: Yinghai Lu Cc: Wanpeng Li Cc: Ingo Molnar Acked-by: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memblock.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memblock.c b/mm/memblock.c index b8d9147e5c08..2cce8b3e76ed 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -771,6 +771,9 @@ static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size, { phys_addr_t found; + if (WARN_ON(!align)) + align = __alignof__(long long); + /* align @size to avoid excessive fragmentation on reserved array */ size = round_up(size, align);