Messages in this thread | | | Date | Tue, 2 Jun 2020 11:41:41 +0200 | From | Peter Zijlstra <> | Subject | Re: PANIC: double fault in fixup_bad_iret |
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On Mon, Jun 01, 2020 at 02:40:31PM +0200, Marco Elver wrote: > I think Peter wanted to send a patch to add __no_kcsan to noinstr: > https://lkml.kernel.org/r/20200529170755.GN706495@hirez.programming.kicks-ass.net > > In the same patch we can add __no_sanitize_address to noinstr. But: > > - We're missing a definition for __no_sanitize_undefined and > __no_sanitize_coverage.
Do those function attributes actually work? Because the last time I played with some of that I didn't.
Specifically: unmarked __always_inline functions must not generate instrumentation when they're inlined into a __no_*san function.
(and that fails to build on some GCC versions, and I think fails to actually work on the rest of them, but I'd have to double check)
> - We still need the above blanket no-instrument for x86 because of > GCC. We could guard it with "ifdef CONFIG_CC_IS_GCC".
Right; so all of GCC is broken vs that function attribute stuff? Any plans of getting that fixed? Do we have GCC that care?
Does the GCC plugin approach sound like a viable alternative implementation of all this?
Anyway, we can make it:
KASAN := SANITIZER_HAS_FUNCTION_ATTRIBUTES
or something, and only make that 'y' when the compiler is sane.
> Not sure what the best strategy is to minimize patch conflicts. For > now I could send just the patches to add missing definitions. If you'd > like me to send all patches (including modifying 'noinstr'), let me > know.
If you're going to do patches anyway, might as well do that :-)
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