Re: [PATCH 3/3] perf report: don't crash on invalid inline debug information

[Milian Wolff <milian.wolff@kdab.com>]

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On Donnerstag, 27. September 2018 21:10:37 CEST Arnaldo Carvalho de Melo 
wrote:
> Em Wed, Sep 26, 2018 at 03:52:07PM +0200, Milian Wolff escreveu:
> > When the function name for an inline frame is invalid, we must
> > not try to demangle this symbol, otherwise we crash with:
> > 
> > #0  0x0000555555895c01 in bfd_demangle ()
> > #1  0x0000555555823262 in demangle_sym (dso=0x555555d92b90, elf_name=0x0,
> > kmodule=0) at util/symbol-elf.c:215 #2  dso__demangle_sym
> > (dso=dso@entry=0x555555d92b90, kmodule=<optimized out>, kmodule@entry=0,
> > elf_name=elf_name@entry=0x0) at util/symbol-elf.c:400 #3 
> > 0x00005555557fef4b in new_inline_sym (funcname=0x0,
> > base_sym=0x555555d92b90, dso=0x555555d92b90) at util/srcline.c:89 #4 
> > inline_list__append_dso_a2l (dso=dso@entry=0x555555c7bb00,
> > node=node@entry=0x555555e31810, sym=sym@entry=0x555555d92b90) at
> > util/srcline.c:264 #5  0x00005555557ff27f in addr2line
> > (dso_name=dso_name@entry=0x555555d92430
> > "/home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/
> > elf", addr=addr@entry=2888, file=file@entry=0x0,> 
> >     line=line@entry=0x0, dso=dso@entry=0x555555c7bb00,
> >     unwind_inlines=unwind_inlines@entry=true, node=0x555555e31810,
> >     sym=0x555555d92b90) at util/srcline.c:313> 
> > #6  0x00005555557ffe7c in addr2inlines (sym=0x555555d92b90,
> > dso=0x555555c7bb00, addr=2888, dso_name=0x555555d92430
> > "/home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/
> > elf")> 
> >     at util/srcline.c:358
> > 
> > So instead handle the case where we get invalid function names
> > for inlined frames and use a fallback '??' function name instead.
> > 
> > While this crash was originally reported by Hadrien for rust code,
> > I can now also reproduce it with trivial C++ code. Indeed, it seems
> > like libbfd fails to interpret the debug information for the inline
> > frame symbol name:
> > 
> > $ addr2line -e
> > /home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/e
> > lf -if b48 main
> > /usr/include/c++/8.2.1/complex:610
> > ??
> > /usr/include/c++/8.2.1/complex:618
> > ??
> > /usr/include/c++/8.2.1/complex:675
> > ??
> > /usr/include/c++/8.2.1/complex:685
> > main
> > /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/mai
> > n.cpp:39
> > 
> > I've reported this bug upstream and also attached a patch there
> > which should fix this issue:
> > https://sourceware.org/bugzilla/show_bug.cgi?id=23715
> 
> Millian, what about this one, which is the cset it is fixing?

Hey Arnaldo,

just noticed this email and that the corresponding patch hasn't landed in 
perf/core yet. The patch set which introduced this is a64489c56c307 ("perf 
report: Find the inline stack for a given address"). Note that the code was 
introduced by this patch, but then subsequently touched and moved by follow up 
patches. So, is this the patch you want to see referenced? Otherwise, the 
latest patch which gets fixed is afaik: 7285cf3325b4a ("perf srcline: Show 
correct function name for srcline of callchains").

Can you please pick either of these patches and amend the commit message of my 
patch and push it to perf/urgent and perf/core?

Cheers
-- 
Milian Wolff | milian.wolff@kdab.com | Senior Software Engineer
KDAB (Deutschland) GmbH, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt, C++ and OpenGL Experts

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