For debian
Even if it hard to make the failure happen
I manage to make it happen by adding a expensive compilation snippet to
libvirt-utils.c and loop on the package building
after some timen it fails with this log:
creating build/temp.linux-x86_64-cpython-314/build
building 'libvirtmod_qemu' extension
creating build/temp.linux-x86_64-cpython-314/build
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
build/libvirt.c -o build/temp.linux-x86_64-cpython-314/build/libvirt.o
-Ibuild -Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
build/libvirt-qemu.c -o
build/temp.linux-x86_64-cpython-314/build/libvirt-qemu.o -Ibuild
-Wp,-DPy_LIMITED_API=0x03060000
building 'libvirtmod_lxc' extension
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
build/libvirt-lxc.c -o
build/temp.linux-x86_64-cpython-314/build/libvirt-lxc.o -Ibuild
-Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
libvirt-qemu-override.c -o
build/temp.linux-x86_64-cpython-314/libvirt-qemu-override.o -Ibuild
-Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
libvirt-lxc-override.c -o
build/temp.linux-x86_64-cpython-314/libvirt-lxc-override.o -Ibuild
-Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
libvirt-utils.c -o build/temp.linux-x86_64-cpython-314/libvirt-utils.o
-Ibuild -Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
libvirt-utils.c -o build/temp.linux-x86_64-cpython-314/libvirt-utils.o
-Ibuild -Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
typewrappers.c -o build/temp.linux-x86_64-cpython-314/typewrappers.o
-Ibuild -Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
typewrappers.c -o build/temp.linux-x86_64-cpython-314/typewrappers.o
-Ibuild -Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-z,relro
-g -fwrapv -O2 -Wl,-z,relro -Wl,-z,now -g -O2
-Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2
build/temp.linux-x86_64-cpython-314/build/libvirt-lxc.o
build/temp.linux-x86_64-cpython-314/libvirt-lxc-override.o
build/temp.linux-x86_64-cpython-314/libvirt-utils.o
build/temp.linux-x86_64-cpython-314/typewrappers.o
-L/usr/lib/x86_64-linux-gnu -lvirt-lxc -lvirt -o
build/lib.linux-x86_64-cpython-314/
libvirtmod_lxc.cpython-314-x86_64-linux-gnu.so
/usr/bin/x86_64-linux-gnu-ld.bfd: cannot find
build/temp.linux-x86_64-cpython-314/typewrappers.o: No such file or
directory
x86_64-linux-gnu-gcc -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-z,relro
-g -fwrapv -O2 -Wl,-z,relro -Wl,-z,now -g -O2
-Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2
build/temp.linux-x86_64-cpython-314/build/libvirt-qemu.o
build/temp.linux-x86_64-cpython-314/libvirt-qemu-override.o
build/temp.linux-x86_64-cpython-314/libvirt-utils.o
build/temp.linux-x86_64-cpython-314/typewrappers.o
-L/usr/lib/x86_64-linux-gnu -lvirt-qemu -lvirt -o
build/lib.linux-x86_64-cpython-314/
libvirtmod_qemu.cpython-314-x86_64-linux-gnu.so
collect2: error: ld returned 1 exit status
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
libvirt-override.c -o
build/temp.linux-x86_64-cpython-314/libvirt-override.o -Ibuild
-Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
libvirt-utils.c -o build/temp.linux-x86_64-cpython-314/libvirt-utils.o
-Ibuild -Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -I. -I/usr/include/python3.14 -c
typewrappers.c -o build/temp.linux-x86_64-cpython-314/typewrappers.o
-Ibuild -Wp,-DPy_LIMITED_API=0x03060000
x86_64-linux-gnu-gcc -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-z,relro
-g -fwrapv -O2 -Wl,-z,relro -Wl,-z,now -g -O2
-Werror=implicit-function-declaration
-ffile-prefix-map=/src/libvirt-python-12.0.0=. -fstack-protector-strong
-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-Wdate-time -D_FORTIFY_SOURCE=2
build/temp.linux-x86_64-cpython-314/build/libvirt.o
build/temp.linux-x86_64-cpython-314/libvirt-override.o
build/temp.linux-x86_64-cpython-314/libvirt-utils.o
build/temp.linux-x86_64-cpython-314/typewrappers.o
-L/usr/lib/x86_64-linux-gnu -lvirt -o build/lib.linux-x86_64-cpython-314/
libvirtmod.cpython-314-x86_64-linux-gnu.so
error: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1
ERROR Backend subprocess exited when trying to invoke build_wheel
E: pybuild pybuild:485: build: plugin pyproject failed with: exit code=1:
python3.14 -m build --skip-dependency-check --no-isolation --wheel --outdir
/src/libvirt-python-12.0.0/.pybuild/cpython3_3.14
dh_auto_build: error: pybuild --build -i python{version} -p 3.14
--parallel=16 returned exit code 13
make: *** [debian/rules:14: binary] Error 25
dpkg-buildpackage: error: debian/rules binary subprocess failed with exit
status 2
debuild: fatal error at line 1185:
dpkg-buildpackage -us -uc -ui -b failed
On Thu, Mar 26, 2026 at 9:05 AM Hector Cao <[email protected]> wrote:
> Hello Matthias,
>
> Thanks for your feedback
>
> libvirt-python contains several extensions: libvirtmod, libvirtmod_qemu,
> libvirtmod_lxc
> those extensions use common source files (typewrappers.c, libvirt-utils.c)
>
> The fact that we enable parallel build and the build of all extensions are
> done in the same folder might lead to
> race condition that can lead to undeterministic output of the build
>
> Right now, enabling -lto seems to increase the occurrence of this race
> condition but I am not surprised if that happens
> in other conditions.
>
> On Tue, Mar 24, 2026 at 1:17 PM Matthias Klose <[email protected]> wrote:
>
>> Control: tags -1 + moreinfo
>>
>> how does this relate to an internal compiler error?
>>
>>
>
> --
> Hector CAO
> Software Engineer – Server Team / Virtualization
> [email protected]
> https://launc <https://launchpad.net/~hectorcao>hpad.net/~hectorcao
> <https://launchpad.net/~hectorcao>
>
> <https://launchpad.net/~hectorcao>
>
--
Hector CAO
Software Engineer – Server Team / Virtualization
[email protected]
https://launc <https://launchpad.net/~hectorcao>hpad.net/~hectorcao
<https://launchpad.net/~hectorcao>
<https://launchpad.net/~hectorcao>
