Re: Clock control algorithms (Re: [RFC][PATCH 5/7] x86: Use latchdata structure for cyc2ns)

[Andy Lutomirski]

On Sat, Nov 30, 2013 at 9:34 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> There is a huge difference between something that breaks after 2^32 and 2^64 events.  Very few computers will ever be able to have 2^64 events of any kind in their lifetime, never mind a single boot.

Given that struct seqcount contains an "unsigned" counter, the 32-bit
wraparound thing could be a problem in practice.  I hope there aren't
security vulnerabilities in which userspace overflows a kernel
refcount, seqcount, or other similar structure.

--Andy
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