[Buildroot] random segmentation fault during built

[Peter Seiderer]

Hello Bin,

re-added CC: buildroot at busybox.net

On Sun, 17 Jan 2021 23:58:04 +0800, Bin Meng <bmeng.cn at gmail.com> wrote:

> Hi Peter,
>
> On Sun, Jan 17, 2021 at 11:30 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> >
> > Hi Peter,
> >
> > On Tue, Jan 12, 2021 at 3:30 AM Peter Seiderer <ps.report at gmx.net> wrote:
> > >
> > > Hello Bin,
> > >
> > > On Mon, 11 Jan 2021 09:11:48 +0800, Bin Meng <bmeng.cn at gmail.com> wrote:
> > >
> > > > Hi Peter,
> > > >
> > > > On Mon, Jan 11, 2021 at 12:04 AM Peter Seiderer <ps.report at gmx.net> wrote:
> > > > >
> > > > > Hello Bin,
> > > > >
> > > > > On Sun, 10 Jan 2021 21:57:45 +0800, Bin Meng <bmeng.cn at gmail.com> wrote:
> > > > >
> > > > > > Hi,
> > > > > >
> > > > > > I see a random segmentation fault during the build of buildroot. For example,
> > > > > >
> > > > > > Makefile:13408: recipe for target 'install-pylibmountexecPYTHON' failed
> > > > > > make[4]: *** [install-pylibmountexecPYTHON] Segmentation fault (core dumped)
> > > > > > make[4]: *** Waiting for unfinished jobs....
> > > > > >
> > > > > > Type "make" for the 2nd time with nothing changed, or rarely a 3rd
> > > > > > time, get a PASS build.
> > > > > >
> > > > > > This was observed by builds on Ubuntu 16.04 and Ubuntu 20.04 hosts.
> > > > > > Any ideas of what could be wrong?
> > > > >
> > > > > In case the errors are at random packages/locations (and succeed on iteration)
> > > > > check your hardware and/or memory, see e.g. [1]...
> > > > >
> > > > > Early versions of the AMD Ryzen CPU had heavy-load segfault bug, see [2]...
> > > > >
> > > > > Regards,
> > > > > Peter
> > > > >
> > > > > [1] https://tldp.org/FAQ/sig11/html/index.html
> > > > > [2] https://techreport.com/news/32459/amd-ships-revised-ryzen-cpus-with-a-compile-bug-fix/
> > > >
> > > > Thank you. I checked the above 2 links and suspect it's not related.
> > > >
> > > > The issue happens on one Intel Xeon CPU with a Ubuntu 16.04 and one
> > > > Intel CORE i9 with a Ubuntu 20.04. The segmentation fault seems to
> > > > happen randomly during package "make install" phase.
> > >
> > > Back to the first question: random packages/locations or always at the same (or
> > > similar) location? Always some python (related) package?
> >
> > Looks it's random, not always some Python packages. For example, I saw
> > this today:
> >
> > make[3]: *** [Makefile:1826: install-pkgconfDATA] Segmentation fault
> > make[3]: *** Waiting for unfinished jobs....
> >
> > >
> > > Which buildroot version? Mind to share your .config file?
> >
> > The current buildroot HEAD with commit
> > 6d4f1324d4a4a23938e40cc12a033a3a264b4ec1, plus my patch:
> > http://patchwork.ozlabs.org/project/buildroot/patch/1610355672-3008-3-git-send-email-bmeng.cn@gmail.com/
> >
> > .config file attached
> >
> > >
> > > Mind to enable core-dump ('ulimit -c unlimited') and take a look at the core
> > > file?
> > >
> >
> > Sorry I did not enable core dump. I will have to turn it on now.
>
> Without any change, I ran a second time build with my configuration
> with core dump enabled, and hit the segmentation fault during "make
> install" another package:
>
> make[4]: *** [Makefile:8649: install-dist_calcxxDATA] Segmentation
> fault (core dumped)
>
> I now got 4 core dump files. 3 of which are generated by conftest, and
> the other one is by sh.
>
> $ find . -name *conftest*
> ./output/build/linux-headers-5.10/scripts/kconfig/tests/conftest.py
> ./dl/linux/git/scripts/kconfig/tests/conftest.py
>
> This looks like Python related. I am not sure how to debug this core
> dump. Do you have any idea? Thanks!

Normally 'file <core_file>' should give a hint which command failed
(or on modern systems the output of dmesg or with systemd core
facility 'coredumpctl dump') and then you can examine the core file
with gdb, e.g.:

	$ gdb <cmd> <core_file>

and from the gdb command prompt call 'where' (in case install the missing
debuginfos as announced by gdb)...

Regards,
Peter


>
> Regards,
> Bin