path: root/mm/memblock.c
diff options
authorVineet Gupta <>2013-04-29 22:06:15 (GMT)
committerLinus Torvalds <>2013-04-29 22:54:28 (GMT)
commit94f3d3afb65f27d4e7b8251e323c6418982cb9c7 (patch)
tree09bf2a9c53e631aebae6cd011122089a00bb8ca6 /mm/memblock.c
parent369a713e9678227e203b53931ad1a10cd8eac811 (diff)
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 <>
Diffstat (limited to 'mm/memblock.c')
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/memblock.c b/mm/memblock.c
index b8d9147..2cce8b3 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);