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Message-ID: <5413BB4D.10606@cloudius-systems.com>
Date: Sat, 13 Sep 2014 06:34:37 +0300
From: Avi Kivity <avi@cloudius-systems.com>
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To: Jiri Olsa <jolsa@redhat.com>
CC: Arnaldo Carvalho de Melo <acme@kernel.org>, linux-kernel@vger.kernel.org,
        David Ahern <dsahern@gmail.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Namhyung Kim <namhyung@kernel.org>, Paul Mackerras <paulus@samba.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Stephane Eranian <eranian@google.com>,
        Jan Stancek <jstancek@redhat.com>
Subject: Re: [BUG] perf tools: Demangle kernel and kernel module symbols too
References: <20140906184631.GA6059@krava.brq.redhat.com>
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On 09/06/2014 09:46 PM, Jiri Olsa wrote:
> hi,
> Jan Stancek found test 1 breakage, probably caused by following patch:
>    950b8354716e perf tools: Demangle kernel and kernel module symbols too
>
> it seems to break test 1:
> ---
> [jolsa@krava perf]$ ./perf test -v 1
>   1: vmlinux symtab matches kallsyms                        :
> --- start ---
> test child forked, pid 6288
> Looking at the vmlinux_path (6 entries long)
>
> SNIP
>
> 0xffffffff8142dba0: diff name v: event_queue virtual table k: __vt_event_queue
> 0xffffffff8142dc00: diff name v: event_dequeue virtual table k: __vt_event_dequeue
> 0xffffffff8142dd90: diff name v: event_wait::isra::::part:: virtual table k: __vt_event_wait.isra.0.part.1
> ---
>
> Avi,
> could you please update the tests/vmlinux-kallsyms.c to reflect
> the demangle change?
>
>

It's not a simple matter of updating the test: the demangler interprets 
name beginning with __vt as C++ mangles names, which of course they aren't.

The only way I see to proceed is to make the demangling optional, 
default off.