Messages in this thread | | | Date | Wed, 14 Jan 2015 12:57:49 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH v2] perf: fix dwarf unwind using libunwind. |
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On Wed, Jan 14, 2015 at 10:36:47AM +0800, Wang Nan wrote: > Perf tool fails to unwind user stack if the event raises in a shared
SNIP
> + > __attribute__ ((noinline)) > static int krava_3(struct thread *thread) > { > - return unwind_thread(thread); > + struct thread *array[2] = {thread, thread}; > + void *fp = &bsearch; > + /* > + * make _bsearch a volatile function pointer to > + * prevent potential optimization, which may expand > + * bsearch and call compare directly from this function, > + * instead of libc shared object. > + */ > + void *(*volatile _bsearch)(void *, void *, size_t, > + size_t, int (*)(void *, void *)); > + > + _bsearch = fp; > + _bsearch(array, &thread, 2, sizeof(struct thread **), compare); > + return global_unwind_retval; > }
ah, I've got confused with the NO_LIBUNWIND_DEBUG_FRAME name and got the impression that we could use it in the tests/make as another compile option test..
but your change is even better ;-) thanks for updating this test
Acked-by: Jiri Olsa <jolsa@kernel.org>
thanks, jirka
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