Messages in this thread | | | Date | Tue, 20 Mar 2007 20:21:19 +0100 | From | Andi Kleen <> | Subject | Re: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt ops callsites to make them patchable |
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On Tue, Mar 20, 2007 at 10:27:00AM -0700, Linus Torvalds wrote: > > > On Tue, 20 Mar 2007, Andi Kleen wrote: > > > > The code never did that. In fact many of the problems we had initially > > especially came out of that -- the fallback code that would handle > > this case wasn't fully correct. > > I don't keep my emails any more, but you *never* fixed the problems in > arch/*/kernel/traps.c.
I fixed that one after you dropped it (hmm, double checking: or at least I thought I had fixed it, but don't see the code right now; will redo then) Basically it was just a one liner anyways - always check against all the stacks that are there.
> Yes, the kernel/unwind.c issues generally got fixed. The infinite loops in > the *callers* never did.
There was later a weaker form that should have caught most loops, but admittedly it wasn't 100% bullet-proof with exception stacks.
> > > Also frankly often your analysis about what went wrong was just > > incorrect. > > Still in denial, I see. > > Do you still claim that "the fallback position always did the right > thing"
No initially it was buggy and that caused several of the crashes.
> Despite the fact that the unwinder had sometimes *corrupted* the > incoming information so much that the fallback position was the one that > oopsed? And no, you didn't fix that.
No, it oopsed because it was broken by itself. Anyways that got fixed quickly.
> > And no, IT DID NOT use probe_kernel_address like you still claim.
There definitely was a patch that made it use it. You might have not merged it though.
> Anyway, you work for Suse, I don't care what you do to the Suse kernel. > Maybe it will get stable some day. Somehow, I doubt it.
So what is your proposed alternative to handle long backtraces? You didn't answer that question. Please do, I'm curious about your thoughts in this area.
-Andi
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