> generate_initcall_order.pl, which orders initcalls for Clang LTO, forks
> a child per input file, up to the job count scripts/jobserver-exec
> passes it in PARALLELISM. It used to run from link-vmlinux.sh, which
> the top-level Makefile invokes as a recursive recipe, but
> commit 5d45950dfbb15 ("kbuild: move vmlinux.o link to
> scripts/Makefile.vmlinux_o") moved it into a recipe without "+".
>
> GNU Make passes the jobserver pipe only to recipes it treats as
> recursive, and the make 4.3 in CentOS Stream 9 also hides it in
> sub-makes (a backport of the fix for GNU Make bug 58232), so
> jobserver-exec cannot open it and prints:
>
> WARNING: Unable to reopen jobserver read-side pipe: FileNotFoundError(2,
> 'No such file or directory')
>
> PARALLELISM is then left unset, and the script caps its children at the
> number of online CPUs instead of the free job slots.
>
> Mark the recipe as recursive again.
>
> Tested ARCH=x86_64 defconfig with CONFIG_LTO_CLANG_THIN=y, LLVM=1
> (Clang 24.0.0git), and GNU Make 4.3 plus CentOS Stream 9's
> make-4.3-cloexec.patch.
>
> Fixes: 5d45950dfbb15 ("kbuild: move vmlinux.o link to
> scripts/Makefile.vmlinux_o")
> Assisted-by: LLM
> Signed-off-by: Kees Cook <[email protected]>
> ---
> scripts/Makefile.vmlinux_o | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
> index 24a3a4fd271c..0b37bd5dc3a4 100644
> --- a/scripts/Makefile.vmlinux_o
> +++ b/scripts/Makefile.vmlinux_o
> @@ -19,7 +19,7 @@ quiet_cmd_gen_initcalls_lds = GEN $@
>
> .tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
> vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
> - $(call if_changed,gen_initcalls_lds)
> + +$(call if_changed,gen_initcalls_lds)
b4 hinted me on [1], where a similar fix was rejected; but as we know
have more arguments to generate_initcall_order.pl
($(KBUILD_VMLINUX_LIBS)), the situation is slightly different.
Thanks!
Reviewed-by: Nicolas Schier <[email protected]>
[1]:
https://lore.kernel.org/all/CAK7LNARCM=rUm8mA8GRQ7ufeyfneGf4OEvHmESKt=zuxs2k...@mail.gmail.com/
--
Nicolas
