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Date: Thu, 13 Jun 2024 13:26:39 +0300
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Subject: Re: [PATCH 2/2] perf: disasm: prefer symsrc_filename for filename
To: duchangbin <changbin.du@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>,
 Arnaldo Carvalho de Melo <acme@kernel.org>,
 Namhyung Kim <namhyung@kernel.org>, Nathan Chancellor <nathan@kernel.org>,
 Mark Rutland <mark.rutland@arm.com>,
 Alexander Shishkin <alexander.shishkin@linux.intel.com>,
 Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
 "Liang, Kan" <kan.liang@linux.intel.com>,
 Nick Desaulniers <ndesaulniers@google.com>, Bill Wendling
 <morbo@google.com>, Justin Stitt <justinstitt@google.com>,
 "linux-perf-users@vger.kernel.org" <linux-perf-users@vger.kernel.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
 "llvm@lists.linux.dev" <llvm@lists.linux.dev>
References: <20240613063510.348692-1-changbin.du@huawei.com>
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 <395cfff7-9692-4123-96b6-353752007f46@intel.com>
 <39be46d6a5194b6390ed31be67689c6c@huawei.com>
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From: Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
 Business Identity Code: 0357606 - 4, Domiciled in Helsinki
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On 13/06/24 12:43, duchangbin wrote:
> On Thu, Jun 13, 2024 at 11:15:28AM +0300, Adrian Hunter wrote:
>> On 13/06/24 09:35, Changbin Du wrote:
>>> If we already found a debugging version when loading symbols for that dso,
>>> then use the same file for disasm instead of looking up in buildid-cache.
>>
>> In the past, there have been cases where the debugging version has not
>> worked for reading object code.  I don't remember the details, but the
>> symbols and debugging information was OK while the object code was not.
>>
>> In general, using anything other than the file that was actually executed
>> for reading object code seems like a bad idea.
>>
> Is this a platform specific issue? AFAIK, the binary code in debugging and
> non-debugging version should be identical. 

"should be" != "guaranteed to be".  Simpler to avoid the issue and
stick with the file that was actually executed.  We already support
having separate symbol sources, so there should not really be a
problem.