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In a blistering rejection that sent shockwaves through the open-source community, Linux creator Linus Torvalds has blocked all RISC-V architecture updates from entering the Linux 6.17 kernel. The decision came during the critical merge window period and followed what Torvalds characterized as both a timing violation and unacceptable code quality.

The Breaking Point

The RISC-V maintainers submitted their pull request just one day before the Linux 6.17 merge window deadline—a timing Torvalds explicitly warned against due to his international travel schedule. But it was the technical content that drew his harshest criticism. Torvalds singled out the proposed make_u32_from_two_u16() helper function as particularly egregious, calling it "useless garbage that makes the world actively a worse place to live."

"If you write the code out as '(a << 16) + b', you know what it does... In contrast, if you write make_u32_from_two_u16(a,b) you have not a f%^5ing clue what the word order is," Torvalds wrote on the Linux kernel mailing list. "You just made things WORSE, and you added that 'helper' to a generic non-RISC-V file where people are apparently supposed to use it to make other code worse too."

The Fallout

The rejected updates included significant RISC-V enhancements:
- ACPI BGRT support for vendor boot logos
- Control-Flow Integrity for user-space processes
- Performance improvements for endianness routines
- Support for Xmipsexectl, MPXY and RPMI extensions

Torvalds' rejection carries operational consequences: RISC-V improvements will now be delayed until at least Linux 6.18, scheduled for later this year. More importantly, it serves as a stark reminder of the Linux kernel's uncompromising quality standards.

The Bigger Picture

This incident illuminates the ongoing tension between rapid architecture development and the Linux kernel's rigorous maintenance culture. RISC-V's open instruction set architecture represents one of the most significant hardware disruptions in decades, but its Linux integration faces growing pains. Torvalds emphasized that while RISC-V maintainers have latitude within their architecture subtree, pollution of generic kernel headers with questionable abstractions remains strictly forbidden.

The rebuke also highlights the critical importance of timing in kernel development. Maintainers had advance notice of Torvalds' travel schedule, making the last-minute submission particularly egregious. As the final gatekeeper, Torvalds warned: "Sending a big pull request the day before the merge window closes in the hope that I'm too busy to care is not a winning strategy."

For the RISC-V ecosystem, this represents both a setback and a learning opportunity. The architecture's path to mainstream Linux adoption now depends on addressing core maintainability concerns while respecting the kernel's hard-won development processes. As Torvalds put it: "You get to try again in 6.18. EARLY in that merge window. And without the garbage."

Source: Phoronix