Messages in this thread | | | Date | Wed, 31 Mar 2010 11:15:49 +0900 | From | Tejun Heo <> | Subject | Re: [PATCH] modules fix incorrect percpu usage |
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On 03/31/2010 11:03 AM, Steven Rostedt wrote: > I don't know. A possible "NULL pointer dereference" seems to me to be a > pretty big user visible impact. > > I guess the question is, what's the risk of adding this change?
AFAICS, the risk is fairly low. per_cpu_ptr(pcpudest, cpu) is SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu))) which is just a fancy way of saying "typeof(ptr)((unsigned long)(ptr) + per_cpu_offset(cpu))" with enough obfuscation to prevent gcc from optimizing it incorrectly.
Thanks.
-- tejun
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