Re: [GIT PULL 0/6] perf/core fixes and improvements

From: Arnaldo Carvalho de Melo
Date: Fri Oct 14 2011 - 11:08:07 EST


Em Fri, Oct 14, 2011 at 09:16:10AM +0200, Ingo Molnar escreveu:
> Hm, got a segfault with a plain 'perf top' on a 3.0-0.rc7.git3-ish
> box:
>
> ./perf top
> Segmentation fault (core dumped)
>
> It took about 20 attempts to reproduce the segfault, and it always
> occured right after the first refresh (which, unlike the working
> cases showed zero samples):
>
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x7ffff13a3700 (LWP 21657)]
> ui_browser__hists_seek (whence=<optimized out>, offset=0,
> self=0x7fffec0008c0)
> at util/ui/browsers/hists.c:682
> 682 h->row_offset = 0;
> (gdb)
>
> (gdb) bt
> #0 ui_browser__hists_seek (whence=<optimized out>, offset=0, self=0x7fffec0008c0)

browser->top was NULL at that point, it was only being initialized in
the refresh routine, fixed in my tree, please re-pull.

One can easily trigger it by specifying a seldom ocurring event, which
will start the browser without samples, then generating such event, I
used net:netif_rx + ping on my workstation.

> Btw., a side note: could we try to reset the console on segfaults and
> similar crashes? TUI crashes tend to leave the console in a messed up
> (blue, etc.) state.

I'll work on that, and also on allowing changing the browser colors,
say, to look like the stdio one.

- Arnaldo
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