Hi,I checked the reported address in libgtk. GDB could map it to the source files. Also, once, I read at Stackoverflow that perf gives up on printing the backtrace (truncates the output backtrace), whenever it detects a binary file without debug info. Could you describe more about this situation? And dear Mr. Olsa, if these cases do not occur on your system, could you tell me how you installed the debug info for the binaries on your system, please?
Regards. On 2020-03-30 23:35, ahmadkhorrami wrote:
Hi,Sorry, I did not pay attention to the fact that we need debug info to be able to decode the callchain. So, without complete debug info the backtrace (either the symbols or the addresses) is bogus. But you say that the backtrace portions containing binaries with full debug info are OK. Am I right? Please confirm if this is the case.If so, these portions may be enough for my current usecase. Regards. On 2020-03-30 18:19, ahmadkhorrami wrote: Hi,thanks, but I still do not understand the cause of the problem. It seems that it is purely a software bug and the callchain addresses seem wrong,by themselves. Am I right?Regards. On 2020-03-30 17:37, Jiri Olsa wrote:On Mon, Mar 30, 2020 at 08:09:53AM +0200, Milian Wolff wrote: On Sonntag, 29. März 2020 21:20:10 CEST Jiri Olsa wrote: On Sun, Mar 29, 2020 at 03:50:57PM +0200, Milian Wolff wrote: On Sonntag, 29. März 2020 14:39:33 CEST ahmadkhorrami wrote: Thanks. I did both of your changes. Perhaps some outputs are revised.But I still have repeated function calls and the script detects them. Here is one of them when the sampling period is 1000 events: <snip> Here, we have two consecutive "7f91788120b5 gtk_widget_propagate_state+0x195 (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2200.30) gtkwidget.c:0" lines, while "gtk_widget_propagate_state+0x195" is not recursive. It should call "gtk_container_forall", which does not occur even after the second (inner) call. Potentially you are just lacking some debug symbols here for this GTK library. note that "gtkwidget.c:0" is bogus already - the line numbersstart with 1, so could we just skip those then? pass on all zero lined inlinesand not add/display themI guess so - but quite frankly I'm a bit uneasy to do this without further exploration about the actual causes here. Afaik DWARF does not say anything about the validity, so in theory there might be some language/compiler thatencodes valid DWARF locations with line 0?Generally, it would be quite interesting to figure out why there is /some/ DWARF data here such that the code thinks it's able to decode the inline framebut then fails and leads to this confusing result? right, but it's beyond my DWARF expertise ;-) we'll need to wait till one of you guys could take a look on it thanks, jirka
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