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[Question] for duplicate symbols, kallsyms and vmlinux may retain different symbol

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I try to fix the failure of testcase 'test__vmlinux_matches_kallsyms', 
and meet a kind of failure because of duplicate symbols.

For example,two functions:
kretprobe_trampoline_holder and kretprobe_trampoline

(1)They all start from the same addr,0x011b180;

(2)kretprobe_trampoline_holder is STB_LOCAL,
    kretprobe_trampoline is STB_GLOBAL;

(3) for kallsyms, because we cann't get the correct size of each symbol 
from /proc/kallsyms, before symbols__fixup_duplicate(), perf assumes 
each symbol's size is zero, so when choose_best_symbol(), we get 
kretprobe_trampoline because perf prefers 'a global symbol over a 
non-global one';

(4) for vmlinux, by readelf, I found that:
size of kretprobe_trampoline_holder is 4, not zero;
size of kretprobe_trampoline is zero;
So when choose_best_symbol(), we get pretprobe_trampoline_holder instead 
because perf prefers 'A symbol with non-zero length' and this condition 
is judged before 'prefer a global symbol';

I have a idea to fix this problem, but may be inappropriate:
Could we move the judge of symbol size to the bottom of the judge 
whether a symbol is global?

Anyone else have good idea?

Song Shan Gong

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[PATCH RFC V1] perf tests: ignore symbols before kernel start Song Shan Gong <gongss@linux.vnet.ibm.com> - 2016-07-19 11:10 +0200
  [Question] for duplicate symbols, kallsyms and vmlinux may retain  different symbol Songshan Gong <gongss@linux.vnet.ibm.com> - 2016-07-19 13:20 +0200

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