Re: [PATCHSET 0/6] perf tools: A couple of TUI improvements

[Namhyung Kim]

Hi Ingo,

On Thu, 19 Dec 2013 13:14:35 +0100, Ingo Molnar wrote:
> * Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
>> Hello,
>> 
>> I was playing with TUI code and added two new windows.  One for
>> showing log messages and another for showing header information.
>> (Maybe they can be implemented on the GTK code too someday.)
>> 
>> Please try to use it! :)
>> 
>> I put the patches on 'perf/tui-v1' branch in my tree:
>> 
>>   git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
>> 
>> Any feedbacks are more than welcome, thanks
>> Namhyung
>
> In the morning haze it took me some time to figure out that typing 'l' 
> gives leads to the log window, 'i' to the header information.
>
> 'l' seems to work (no log messages though :-), but in perf-top 'i' 
> segfaulted:
>
>   comet:~/tip/tools/perf> perf top
>   perf: Segmentation fault

Ah, forgot to test perf top - I just played with perf report at this
time. :-/

>
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x7ffff0d39700 (LWP 14785)]
> perf_header__fprintf_info (session=session@entry=0x957bf0, fp=fp@entry=0x7fffec000a30, full=full@entry=true) at util/header.c:2195
> 2195            int fd = perf_data_file__fd(session->file);
> Missing separate debuginfos, use: debuginfo-install audit-libs-2.3.2-1.fc19.x86_64 bzip2-libs-1.0.6-8.fc19.x86_64 elfutils-libelf-0.156-5.fc19.x86_64 elfutils-libs-0.156-5.fc19.x86_64 glibc-2.17-19.fc19.x86_64 libgcc-4.8.2-1.fc19.x86_64 libunwind-1.1-2.fc19.x86_64 nss-softokn-freebl-3.15.2-2.fc19.x86_64 numactl-libs-2.0.8-4.fc19.x86_64 perl-libs-5.16.3-266.fc19.x86_64 python-libs-2.7.5-9.fc19.x86_64 slang-2.2.4-8.fc19.x86_64 xz-libs-5.1.2-4alpha.fc19.x86_64 zlib-1.2.7-10.fc19.x86_64
> (gdb) bt
> #0  perf_header__fprintf_info (session=session@entry=0x957bf0, fp=fp@entry=0x7fffec000a30, full=full@entry=true) at util/header.c:2195
> #1  0x00000000004ce3fe in tui__header_window (env=env@entry=0x957c30) at ui/browsers/header.c:92
> #2  0x00000000004cbdfd in perf_evsel__hists_browse (evsel=evsel@entry=0x957560, nr_events=nr_events@entry=1, 
>     helpline=helpline@entry=0x57db88 "For a higher level overview, try: perf top --sort comm,dso", ev_name=0x957870 "cycles", left_exits=left_exits@entry=false, 
>     hbt=hbt@entry=0x7ffff0d38ea0, min_pcnt=min_pcnt@entry=0, env=env@entry=0x957c30) at ui/browsers/hists.c:1491
> #3  0x00000000004cd5a5 in perf_evlist__tui_browse_hists (evlist=0x8e5930, help=help@entry=0x57db88 "For a higher level overview, try: perf top --sort comm,dso", 
>     hbt=hbt@entry=0x7ffff0d38ea0, min_pcnt=0, env=0x957c30) at ui/browsers/hists.c:1957
> #4  0x0000000000433b48 in display_thread_tui (arg=0x7fffffffb150) at builtin-top.c:584
> #5  0x0000003e59407c53 in start_thread () from /lib64/libpthread.so.0
> #6  0x0000003e590f5dbd in clone () from /lib64/libc.so.6
> (gdb) 
>
> I suspect it got surprised by perf top not having a header per se? 
> Still it might make sense to also robustify 
> perf_header__fprintf_info() against segfaulting and such.

Right.  To be precise, perf top do have header.env but not set the
actual info in it.  I had to check it, sorry.  The patch below will fix
the problem.