Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 23 Feb 2012 14:38:42 -0800 | Subject | Re: [PATCH 0/5] i387: stable kernel backport |
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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.
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.
Linus
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