Re: [musl] Better backtrace from core dump

["Timo Teräs" <timo.teras@iki.fi>]

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Hi

Install musl-dbg package to get the debug symbols.

Timo

On Tue, 23 Jun 2020, 14.43 Michal Nowak, <mnowak@isc.org> wrote:

> Hi,
>
> in GitLab we have jobs which run BIND system tests on different
> operating system, mostly in Docker on Debian 10 but too in KVM virtual
> machines for non-Linux operating systems. If the test produces core
> dump, we generate backtrace out of it while still in the CI.
>
> For all C libraries but for musl we get reasonable backtraces, e.g.
> https://gitlab.isc.org/isc-projects/bind9/-/jobs/970585, but for Alpine
> Linux 3.11 (musl 1.1.24-r2 & GCC 9.2.0-r4) we get something like this
> (https://gitlab.isc.org/isc-projects/bind9/-/jobs/970568):
>
> warning: Can't read pathname for load map: No error information.
> Core was generated by
> `/builds/isc-projects/bind9/bin/named/.libs/lt-named -D statistics-ns3
> -X named.'.
> Program terminated with signal SIGABRT, Aborted.
> #0  0x00007fb708ec39ee in setjmp () from /lib/ld-musl-x86_64.so.1
> [Current thread is 1 (LWP 1274)]
> #0  0x00007fb708ec39ee in setjmp () from /lib/ld-musl-x86_64.so.1
> #1  0x00007fb708ec3b49 in raise () from /lib/ld-musl-x86_64.so.1
> #2  0x804ad6685d596f46 in ?? ()
> #3  0x00007fb708bd1030 in ns_modules () from
> /builds/isc-projects/bind9/lib/ns/.libs/libns.so.1702
> #4  0x00007fb708e59edf in ?? () from
> /builds/isc-projects/bind9/lib/isc/.libs/libisc.so.1702
> #5  0x0000000042756621 in ?? ()
> #6  0x00007fb7069c9db0 in ?? ()
> #7  0x0000001800000018 in ?? ()
> #8  0x00007fb708f0e873 in ?? () from /lib/ld-musl-x86_64.so.1
> #9  0x0000000000000008 in ?? ()
> #10 0x00007fb7069ca0e8 in ?? ()
> #11 0x00007fb7069ca0d0 in ?? ()
> #12 0x00007fb708e32d12 in isc_hash_function (data=0x459, length=0,
> case_sensitive=<optimized out>) at hash.c:117
>
> This is how we generate the backtrace:
>
>    "${top_builddir}/libtool" --mode=execute gdb --batch
> --command=run.gdb --core="$coredump" -- "$binary"
>
> The GDB command can be either 'bt' or 'thread apply all bt full' (for
> more on the GDB invocation, see
>
> https://gitlab.isc.org/isc-projects/bind9/-/blob/main/bin/tests/system/run.sh.in#L268
> ).
>
> CFLAGS used:
>
>    -fno-omit-frame-pointer -fno-optimize-sibling-calls -O1 -g -Wall -Wextra
>
> This is what we install on top of the stock Alpine Linux 3.11 Docker
> image:
>
> https://gitlab.isc.org/isc-projects/images/-/blob/main/docker/bind9/alpine-template/Dockerfile.
>
> Are there other packages, we should get into the image to get better
> backtraces?
>
> Should we use something else than GDB?
>
> Should we add some compiler flags?
>
> Thanks,
> Michal
>

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