Occasionally, I will forget to link something from the mailing list in this post. To see my full mailing list activity (patches, reviews, and reports), you can view it on lore.kernel.org.
Linux kernel patches
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Build errors: These are patches to fix various build errors that I found through testing different configurations with LLVM or were exposed by our continuous integration setup. The kernel needs to build in order to be run :)
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Miscellaneous fixes and improvements: These are fixes and improvements that don’t fit into a particular category but are important to ClangBuiltLinux.
ARM: Use an absolute path to unified.h in KBUILD_AFLAGS
(v1
)
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Stable backports and fixes: It is important to make sure that the stable trees are as free from issues as possible, as those are the trees that devices and users use; for example, Android and Chrome OS regularly merge from stable, so if there is a problem that will impact those trees that we fixed in mainline, it should be backported.
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Warning fixes: These are patches to fix various warnings that appear with LLVM. I used to go into detail about the different warnings and what they mean, but the important takeaway for this section is that the kernel should build warning free, as all developers should be using
CONFIG_WERROR
, which will turn these all into failures. Maybe these should be in the build failures section…
Patch review and input
For the next sections, I link directly to my first response in the thread when possible but there are times where the link is to the main post. My responses can be seen inline by going to the bottom of the thread and clicking on my name.
Reviewing patches that are submitted is incredibly important, as it helps ensure good code quality due to catching mistakes before the patches get accepted and it can help get patches accepted faster, as some maintainers will blindly pick up patches that have been reviewed by someone that they trust.
Re: [PATCH 1/2] kbuild: set y instead of 1 to KBUILD_{BUILTIN,MODULES}
Re: [PATCH v2 1/4] kbuild: move W=1 check for scripts/misc-check to top-level Makefile
Re: [PATCH] drm/i915/pmu: Fix build error with GCOV and AutoFDO enabled
Add basic support for building Rust
Re: [PATCH] riscv: vdso: Exclude .rodata from the PT_DYNAMIC segment
Re: [PATCH] LoongArch: vDSO: correctly use asm parameters in syscall wrappers
Re: [PATCH v3 1/3] riscv: vdso: Deduplicate CFLAGS_REMOVE_* variables
Re: [PATCH v3 2/3] riscv: vdso: Disable LTO for the vDSO
Re: [PATCH v3 3/3] vdso: Reject absolute relocations during build
Re: [PATCH] kbuild: move warnings about linux/export.h from W=1 to W=2
Re: FAILED: patch "[PATCH] kbuild: userprogs: fix bitsize and target detection on clang" failed to apply to 5.4-stable tree
Re: FAILED: patch "[PATCH] kbuild: hdrcheck: fix cross build with clang" failed to apply to 5.4-stable tree
Issue triage, input, and reporting
The unfortunate thing about working at the intersection of two projects is we will often find bugs that are not strictly related to the project, which require some triage and reporting back to the original author of the breakage so that they can be fixed and not impact our own testing. Some of these bugs fall into that category while others are issues strictly related to this project.
[Clang] Add resource_dir_EQ flag to CC1Option group
Re: [BUG?] clang miscompilation of inline ASM with overlapping input/output registers
Re: [PATCH v4 15/21] drm/i915/flipq: Provide the nuts and bolts code for flip queue
bpf-restrict-fs fails to load without DYNAMIC_FTRACE_WITH_DIRECT_CALLS on arm64
[SelectionDAG] Make `(a & x) | (~a & y) -> (a & (x ^ y)) ^ y` available for all targets
Re: selftests/filesystem: clang warning null passed to a callee that requires a non-null argument [-Wnonnull]
[clang] Reset FileID based diag state mappings
Re: ld.lld: error: Cannot export BSS symbol __inittext_end to startup code
as-instr in Kbuild broken for arch/arm
[Reland] [PowerPC] frontend get target feature from backend with cpu name
Re: [PATCH 5.10 000/352] 5.10.239-rc2 review
Non constant size and offset in DWARF
Tooling improvements
These are changes to various tools that we use, such as our continuous integration setup, booting utilities, toolchain building scripts, or other closely related projects such as AOSP’s distribution of LLVM and TuxMake.
Updates patches (June 2, 2025)
Drop d0afcfeb9e3810ec89d1ffde1a0e36621bb75dca from most upstream stable trees
Disable CONFIG_FORTIFY_KUNIT_TEST for allmodconfig + LTO (part 2)
Drop SCSI QEDF patch from -tip
boot-qemu.py: Fix always downloading LoongArch firmware
Disable RISC-V full LTO build on mainline with LLVM 14
patches: Drop SCSI QEDF patch from several trees
patches: 6.6: Drop -Wdefault-const-init-unsafe patch
generator: yml: Update Alpine Linux configuration links
Update Android LLVM ARM builds
utils.py: Update get_cbl_name() for new Alpine configuration scheme
Update patches (June 25, 2025)
utils.py: Fix get_cbl_name() for Alpine config change for real
patches: stable: Drop iwlwifi fortify workaround
Behind the scenes
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Every day that there is a new linux-next release, I rebase and build a few different kernel trees then boot and runtime test them on several different machines, including a Raspberry Pi 4, a Raspberry Pi 3, a SolidRun Honeycomb LX2, an Ampere Altra Developer Platform, two Intel-based desktops, an AMD-based desktop, and an Intel-based laptop. This is not always visible because I do not report anything unless there is something broken but it can take up to a few hours each day, depending on the amount of churn and issues uncovered.
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I continue to upload prebuilt, fast versions of LLVM for kernel developers and our continuous integration to use.
Special thanks
Special thanks to Google and the Linux Foundation for sponsoring my work.