Messages in this thread | | | Date | Thu, 23 Feb 2012 23:49:27 +0100 | From | Willy Tarreau <> | Subject | Re: [PATCH 0/5] i387: stable kernel backport |
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On Thu, Feb 23, 2012 at 02:38:42PM -0800, Linus Torvalds wrote: > On Thu, Feb 23, 2012 at 2:27 PM, Willy Tarreau <w@1wt.eu> wrote: > > > > OK so indeed I will only be able to check that it boots :-/ > > Well, we could do some trivial test-harness that just forces the issue > with regular timer interrupts (and even without AES-NI). I think Peter > talked about that when we were trying to hunt it down - but I think he > was then able to reproduce the problem without anything special and we > dropped it. > > Essentially, just doing something like > > if (irq_fpu_usable()) { > kernel_fpu_begin(); > kernel_fpu_end(); > } > > in do_irq() and do_softirq() would stress-test things even without > wireless, and even without AES-NI.
Interesting...
> You'd still need an x86-32 machine to test on, because x86-64 was > immune to this issue. > > But yeah, the impact of this seems to be small enough that for older > kernels (which are likely used on older systems for maintenance > anyway) disabling AES-NI on x86-32 really might be the way to go.
I agree. I don't know anybody using AES-NI on purpose on older x86-32 systems!
Willy
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