[Buildroot] [Bug 13166] New: python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[Buildroot] [Bug 13166] New: python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

            Bug ID: 13166
           Summary: python-rpi-gpio: does not work against aarch64,
                    unintentional side-effect of gcc-10 patch
           Product: buildroot
           Version: unspecified
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P5
         Component: Other
          Assignee: unassigned at buildroot.uclibc.org
          Reporter: christian at paral.in
                CC: buildroot at uclibc.org
  Target Milestone: ---

python-rpi-gpio on aarch64 (pi 4):

ImportError:
/usr/lib/python3.8/site-packages/RPi/_GPIO.cpython-38-aarch64-linux-gnu.so:
undefined symbol: high

There is a patch attached to the package - 

  fixes the "multiple definition of" errors with gcc10

  Signed-off-by: Michael Fischer <mf@go-sys.de>

It changes the "high" variable to be "extern" which might have caused this?

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

--- Comment #1 from Christian Stewart <christian@paral.in> ---
According to this, originally the submitter tried to disable the warning, but
that patch was rejected by the maintainers:


http://buildroot-busybox.2317881.n4.nabble.com/PATCH-1-1-package-python-rpi-gpio-fix-build-with-gcc-10-x-td261727.html

Then they submitted another with the more deep changes, I wonder, what was so
bad about disabling the compiler warning?

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

--- Comment #2 from Christian Stewart <christian@paral.in> ---
Created attachment 8566
  --> https://bugs.busybox.net/attachment.cgi?id=8566&action=edit
Removes a faulty patch which caused a "undefined symbol" error at runtime
against aarch64 on a Raspberry Pi.

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

--- Comment #3 from Christian Stewart <christian@paral.in> ---
Here's a patch to fix it by going back to the "disable compiler warning and
paper over the problem" approach, not sure if the maintainers will like it, but
at least it fixed the problem for me in the short term.

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

Yann E. MORIN <yann.morin.1998@free.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |yann.morin.1998 at free.fr

--- Comment #4 from Yann E. MORIN <yann.morin.1998@free.fr> ---
(In reply to Christian Stewart from comment #1)
> I wonder, what was so bad about disabling the compiler warning?

Because duplicate symbols are a source for bugs. If we just add the -fcommon
option, this indeed hides the warning away, but the problematic code will not
get fixed, and we will have to carry that option ad libitum.

Instead, we want patches that fixes those warnings, so those patches are sent
to the corresponding upstreams, so the packages get fixed, and so we can drop
those patches in a future version bump.

So, I've had a look a deeper look at the patch now, and indeed it is not
complete... I'll follow up with a revised fix. Stay tuned to the ML.

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

--- Comment #5 from Christian Stewart <christian@paral.in> ---
Thanks Yann. The patch I attached to this bug actually doesn't work anyway, the
module still fails at runtime:

  File "usr/lib/python3.8/site-packages/RPi/GPIO/__init__.py", line 23, in
<module>
SystemError: Type does not define the tp_name field.

Feel free to send me any patch for testing.

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

Yann E. MORIN <yann.morin.1998@free.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Attachment #8566|0                           |1
        is obsolete|                            |

--- Comment #6 from Yann E. MORIN <yann.morin.1998@free.fr> ---
Created attachment 8571
  --> https://bugs.busybox.net/attachment.cgi?id=8571&action=edit
Fix patch, add runtime test

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

--- Comment #7 from Yann E. MORIN <yann.morin.1998@free.fr> ---
Christian, care to test the attached patch, please?

The runtime test demonstrates that it is possible to import the
module, but I have no way to test it on real hardware for now...

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

--- Comment #8 from Christian Stewart <christian@paral.in> ---
Hi Yann, looks to be working perfectly now. Thanks!

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[Buildroot] [Bug 13166] python-rpi-gpio: does not work against aarch64, unintentional side-effect of gcc-10 patch

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=13166

Yann E. MORIN <yann.morin.1998@free.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #9 from Yann E. MORIN <yann.morin.1998@free.fr> ---
Christian, All,

Fixed with commit ae6bd1eb44. Thanks for the report.

Regards,
Yann E. MORIN.

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