Messages in this thread |  | | From | Linus Torvalds <> | Date | Fri, 10 Feb 2012 11:32:42 -0800 | Subject | Re: [RFC 0/5] kernel: backtrace unwind support |
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On Fri, Feb 10, 2012 at 11:27 AM, Arnaldo Carvalho de Melo <acme@redhat.com> wrote: > > "Vote for --fno-omit-frame-pointer! One register is a cheap price to pay > for not going insane!" > > /me goes back to non political things.
Even with -fomit-frame-pointer (which seems to be a big deal on Atom in particular), the call frames really don't look that horrible even when we guess. And seeing the occasional stale pointer can often give hints about what the thing was doing before, so it's not even horrible.
The biggest problem actually seems to often be some gcc versions that allocate a *lot* of stack space for some functions and then never really use it. That ends up then letting *tons* of really old stale code pointers "shine through".
Sometimes it's our code that just has horrible stack usage with crazy worst-case allocations or something. We've fixed a few of them, it seems to be getting better.
Linus
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