Re: [PATCH] net: fix race in the receive/select

[Andi Kleen]

Jiri Olsa <jolsa@xxxxxxxxxx> writes:

> Adding memory barrier to the __pollwait function paired with 
> receive callbacks.  The smp_mb__after_lock define is added, 
> since {read|write|spin}_lock() on x86 are full memory barriers.

I was wondering did you see that race actually happening in practice?
If yes on which system?

At least on x86 I can't see how it happens. mb() is only a compile
time barrier and the compiler doesn't optimize over indirect callbacks
like __pollwait() anyways.

It might be still needed on some weaker ordered architectures, but did you
actually see it there?

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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