Re: [x86] BUG: unable to handle kernel paging request at 00740060

From: Ingo Molnar
Date: Wed Oct 09 2013 - 10:32:39 EST



* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> > This is what we are going to return. But note that -20(%ebp) was not
> > initialized if TIF_NOTIFY_RESUME was already set, "jc .L2" skips .L5
> > above. IOW, in this case we seem to return a random value from stack.
>
> I think you're quite right, and I can confirm I can reproduce this with
> gcc-4.8.1 and Wu's .config:
>
> [...]
>
> Once I force a x86_64 build using the 'same' config it goes away and
> generates 'sensible' code again [...]

So this at least opens up the possibility that we can create a not too
painful quirk and only use the 'asm goto' optimization tricks on 64-bit
kernels?

Thanks,

Ingo
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