From: Florian Weimer <fweimer@redhat.com>
To: Jacob Kroon via Gdb <gdb@sourceware.org>
Subject: Re: Debugging ld.so in gdb
Date: Fri, 04 Feb 2022 14:58:26 +0100 [thread overview]
Message-ID: <8735kypwcd.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <29e0ef71-4706-9b0f-2a68-e12c54120d8e@gmail.com> (Jacob Kroon via Gdb's message of "Fri, 4 Feb 2022 14:45:33 +0100")
* Jacob Kroon via Gdb:
> Since a week or two I have started to see a segfault on my updated
> Fedora 35 system. I suspect the segfault is related to a recent glibc
> update.
>
> The segfault I see happens when I run the following:
>
> $ ldd ./mylib.so
>
> I narrowed it down to running:
>
> $ LD_TRACE_LOADED_OBJECTS=1 /lib64/ld-linux-x86-64.so.2 ./mylib.so
>
> "coredumpctl info" gives me:
>
>> Stack trace of thread 143567:
>> #0 0x00007ff428f73590 n/a (n/a + 0x0)
>> #1 0x00007ff428f8af0f _dl_map_object_deps (/usr/lib64/ld-linux-x86-64.so.2 + 0x3f0f)
>> #2 0x00007ff428fa6970 dl_main (/usr/lib64/ld-linux-x86-64.so.2 + 0x1f970)
>> #3 0x00007ff428fa2c7c _dl_sysdep_start (/usr/lib64/ld-linux-x86-64.so.2 + 0x1bc7c)
>> #4 0x00007ff428fa4678 _dl_start_final (/usr/lib64/ld-linux-x86-64.so.2 + 0x1d678)
>> #5 0x00007ff428fa36a8 _start (/usr/lib64/ld-linux-x86-64.so.2 + 0x1c6a8)
>
> but inspecting in gdb using "coredumpctl debug" doesn't give me any sane
> backtrace.
>
> The .so is part of a Yocto build. If I copy the file out from its build
> directory to $HOME and run ldd on it, then there is no crash. So I
> suspect RUNPATH is involved somehow since it contains $ORIGIN.
>
> Any ideas of what I can do to investigate further ?
I suggest to run ld.so under GDB, with
set startup-with-shell off
set environment LD_TRACE_LOADED_OBJECTS 1
b _start
run ./mylib.so
record btrace pt
continue
And after the crash, look at
record instruction-history
to see how it reached the crash. This assumes that you have an
execution environment that supports branch tracing.
Thanks,
Florian
next prev parent reply other threads:[~2022-02-04 13:58 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 13:45 Jacob Kroon
2022-02-04 13:58 ` Florian Weimer [this message]
2022-02-04 14:09 ` Jacob Kroon
2022-02-04 14:22 ` Florian Weimer
2022-02-04 14:27 ` Jacob Kroon
2022-02-04 16:09 ` Florian Weimer
2022-02-04 16:53 ` Jacob Kroon
2022-02-04 17:04 ` Florian Weimer
2022-02-04 17:11 ` Jacob Kroon
2022-02-04 17:15 ` Florian Weimer
2022-02-07 8:36 ` Jacob Kroon
2022-02-07 11:46 ` Jacob Kroon
2022-02-07 11:55 ` Florian Weimer
2022-02-07 12:15 ` Jacob Kroon
2022-02-07 12:27 ` Florian Weimer
2022-02-07 12:32 ` Jacob Kroon
2022-02-07 13:39 ` Jacob Kroon
2022-02-07 13:45 ` Jacob Kroon
2022-02-07 13:53 ` Adhemerval Zanella
2022-02-07 13:54 ` Jacob Kroon
2022-02-07 14:07 ` Florian Weimer
2022-02-07 16:28 ` Florian Weimer
2022-02-07 17:04 ` Jacob Kroon
2022-02-04 14:45 ` Jacob Kroon
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