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Build CPython against modern kernel UAPI headers on *-linux-gnu targets - #1163
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Package Debian's linux-libc-dev headers as a build dependency for *-linux-gnu targets. This new linux-uapi package provides userspace header from a modern Linux kernel (currently 7.0.12). When building CPython on *-linux-gnu targets use these headers to enable modern kernel features, such as os.pidfp_open. At runtime if the kernel does not support the needed syscalls ENOSYS will be returned.
Verify that no sysconfig variables contains the build-only linux-uapi path.
Verify that building against the modern Linux UAPI headers enables os.pidfd_open on GNU/Linux targets.
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zanieb
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Jun 25, 2026
This was referenced Jul 9, 2026
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Always build CPython with `os.memfd_create` but remove the Python function from the namespace at runtime when glibc does not provide the an implementation. This is accomplished using a weak `memfd_create` symbol which is evaluated at runtime. This requires the modern kernel UAPI headers from #1163 to define the `MFD_*` constants.
This was referenced Aug 12, 2026
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Use modern Linux kernel UAPI headers when building CPython for glibc Linux targets.
Adds a
linux-uapipackage to the project that contains the unpackedlinux-libc-devpackage from a modern Debian release, currentlytrixie-backports. This provides Linux UAPI headers from a modern kernel release.Building CPython against these headers makes newer syscall definitions and macros available at build time, enabling CPython functionality such as
os.pidfd_open.This does not increase the minimum required glibc or runtime kernel version.
APIs compiled using these definitions may still fail at runtime. For example, if an API uses a direct syscall and the running kernel does not implement it, the kernel returns
ENOSYS, which Python exposes as anOSError.Consequently, functions such as
os.pidfd_openwill exist when running on an older kernel that does not implement the corresponding syscall. Applications should handleOSErrorwitherrno.ENOSYSwhen runtime kernel support is uncertain.This should be included as a quirk of
python-build-standaloneand documented as such. The trade-off here is worth introducing this quirk.Related to #193
Related to astral-sh/uv#11811, astral-sh/uv#9374