Re: Wrong Perf Backtraces

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Sorry. GDB should disassemble functions so that the names are not demangled.

On 2020-03-26 22:49, ahmadkhorrami wrote:

Hi,
Here is the link for the python script:
https://gofile.io/?c=1ZSLwe
It is written in python-3 and takes the perf script output as input.
It looks for consecutive repeated backtrace lines and checks if the function in these lines calls itself at the offset in the line (i.e., checks if recursion is possible). If not possible it reports an error. Could you check to see if any error is detected in your outputs, please?
Regards.
On 2020-03-26 20:09, Jiri Olsa wrote:

On Thu, Mar 26, 2020 at 05:50:27PM +0430, ahmadkhorrami wrote:

Hi,
First of all, many thanks for your time. Did you say that the first file has
problems?

The first file (http://gofile.io/?c=qk6oXv) has repeated gmallocn()s while the second (https://gofile.io/?c=oGxgSM) also has problems with unmatched (not necessarily repeated) function calls. I am not sure if the kernel for the second one is 5.4.7 or the generic Ubuntu kernel. But the first one is
certainly 5.4.7. Just to be clear, there were many instances of these
unmatched <caller, callees>.
I can se all the files, but I just can't see the issue yet
but it's probably because of issues with perf archive..

let's see if somebody else can chime in

I have a simple python script that checks for this situation. It
disassembles functions using GDB and checks the (directly called) target of each caller. I will put some comments in the script and upload it. Could you check to see if the python script detects any mismatches in your backtraces? It takes the perf script output file as input. I will upload the script in
an hour.
ok

jirka



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