Re: [PATCH v3] sched/numa: fix unsafe get_task_struct() in task_numa_assign()

From: Peter Zijlstra
Date: Wed Oct 22 2014 - 12:37:54 EST


On Wed, Oct 22, 2014 at 06:14:50PM +0200, Oleg Nesterov wrote:
> Hmm. so perhaps I misunderstood your concern...
>
> Do you mean that on !x86 a plain LOAD can "corrupt" the memory as it seen
> from another vaddr?

I'm not sure. Stores for sure, loads I'm not sure about.

I suspect loads are OK, the aliasing cacheline will be !modified and
therefore later eviction should discard (not write back). But like said,
I'm not at all sure.

I would hesitate to put such assumptions into generic code -- although
it appears we already have.
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