Messages in this thread | | | Date | Tue, 14 Jul 2015 23:56:49 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v7 2/4] x86/stackvalidate: Compile-time stack validation |
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On Tue, Jul 14, 2015 at 04:30:34PM -0500, Josh Poimboeuf wrote:
> > How (if it does at all) deal with function-trace / -pg -fprofile-arcs > > things? Does it silently ignore the __mcount calls and assumes ftrace > > knows wtf its doing? ;-) > > Adding Steven to CC to keep me honest. > > In the case of "-pg -mfentry", which is what ftrace has relied on for
Ah -mfentry is the magic word, I couldn't find it and a grep led me astray.
> the past few years for newer versions of gcc, stackvalidate silently > ignores __fentry__ calls and assumes that ftrace indeed knows wtf it's > doing. I don't see a problem there as long as the ftrace handler > doesn't sleep.
They should not indeed, however it would be very nice if backtraces would still be 'good'.
> I haven't run stackvalidate on the old "-pg" mcount non-fentry stuff, > but I think it creates a stack frame before calling mcount, so it should > be fine.
Ok.
> I don't know much about -fprofile-arcs, but as far as I can tell, it's > only used for gcov.
Right, nobody much uses that I think.
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