[lldb-dev] [Bug 18769] New: lldb fails to stack unwind gold linker exes that assert

[Todd Fiala]

> this means that lldb is getting back 0x00's when it is trying to read
memory out of the core file I expect.

Yep, I remember that one from last Friday! :-)

> (lldb) im loo -a $pc

I'll give that a shot, thanks Jason.



On Fri, Feb 7, 2014 at 4:01 PM, Jason Molenda <jmolenda at apple.com> wrote:

> I'd start by seeing if lldb knows where the binaries are loaded in this
> session.  e.g.
>
> (lldb) im loo -a $pc
>
> It doesn't look like lldb knows what Module you're in and doesn't have a
> function/symbol name either.  There's probably no eh_frame unwind info and
> IIRC your system's libraries are all built -fomit-frame-pointer so a blind
> stack walk will fail.
>
> I don't know how solid lldb's corefile support is on Linux.  It may be
> that you're not able to find where all the solibs are loaded when doing
> core file debugging.
>
> This is also a little disheartening,
>
> * thread #1: tid = 0, 0x00007ffba3bb2425, name = 'lldb-gdbserver', stop
> reason = signal SIGABRT
>     frame #0: 0x00007ffba3bb2425
> -> 0x7ffba3bb2425:  addb   %al, (%rax)
>    0x7ffba3bb2427:  addb   %al, (%rax)
>    0x7ffba3bb2429:  addb   %al, (%rax)
>    0x7ffba3bb242b:  addb   %al, (%rax)
>
> this means that lldb is getting back 0x00's when it is trying to read
> memory out of the core file I expect.
>
>
>
> On Feb 7, 2014, at 3:49 PM, Todd Fiala <tfiala at google.com> wrote:
>
> > Yeah - I hit "enter" by accident :-)  The next comment fills in the
> rest.  Short version: gdb + gold linker + assert = backtrace, lldb + gold
> linker = assert = failure.
> >
> > Not high priority, but will stop me from using the gold linker even
> though it gives me a 6-7% speed increase.
> >
> >
> > On Fri, Feb 7, 2014 at 3:32 PM, <bugzilla-daemon at llvm.org> wrote:
> > Bug ID        18769
> > Summary       lldb fails to stack unwind gold linker exes that assert
> > Product       lldb
> > Version       unspecified
> > Hardware      PC
> > OS    Linux
> > Status        NEW
> > Severity      normal
> > Priority      P
> > Component     All Bugs
> > Assignee      lldb-dev at cs.uiuc.edu
> > Reporter      tfiala at google.com
> > Classification        Unclassified
> >
> > I'm hitting an assertion in lldb-gdbserver.  On Ubuntu 12.04 x86_64,
> using the
> > gold linker 'sudo apt-get install binutils-gold', with a cmake/ninja
> build, I
> > am not able to get a valid backtrace out of lldb for lldb-gdbserver when
> it
> > generates
> >
> >
> > You are receiving this mail because:
> >       • You are the assignee for the bug.
> >
> > _______________________________________________
> > lldb-dev mailing list
> > lldb-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
> >
> >
> >
> >
> > --
> > Todd Fiala |   Software Engineer |     tfiala at google.com |
> 650-943-3180
> >
> > _______________________________________________
> > lldb-dev mailing list
> > lldb-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
>
>


-- 
Todd Fiala | Software Engineer | tfiala at google.com | 650-943-3180
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