From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
To: Kees Cook <kees@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
Nicolas Schier <nsc@kernel.org>,
Manuel Ebner <manuelebnerli@mailbox.org>,
linux-kbuild@vger.kernel.org,
"Paul E. McKenney" <paulmck@kernel.org>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v1 1/2] kbuild: Mark the kernel image gzip recipes as recursive
Date: Fri, 9 Oct 2026 13:05:00 +0100 [thread overview]
Message-ID: <asjYDiBaS1V5CymE@gremlin> (raw)
In-Reply-To: <20261009062733.3119731-1-kees@kernel.org>
On Thu, Oct 08, 2026 at 11:27:30PM -0700, Kees Cook wrote:
> Since commit 48ebe1cbbeb51 ("kbuild: compress the kernel with pigz if
> available"), cmd_gzip runs pigz through scripts/jobserver-exec, which
> takes the job slots make has free. GNU Make passes the jobserver pipe
> only to recipes it treats as recursive, but leaves --jobserver-auth in
> MAKEFLAGS for all of them. The make 4.3 in CentOS Stream 9 also hides
> the pipe in sub-makes (a backport of the fix for GNU Make bug 58232), so
> jobserver-exec cannot open it, runs pigz on one thread, and prints:
>
> WARNING: Unable to reopen jobserver read-side pipe: FileNotFoundError(2, 'No such file or directory')
>
> Mark the gzip recipes as recursive with "+", as commit ecab4115c44cc
> ("kbuild: mark `rustc` (and others) invocations as recursive") did for
> rustc. As with those, "make -n" now runs them.
>
> Tested ARCH=x86_64 and ARCH=arm64 defconfig with GNU Make 4.3 plus
> CentOS Stream 9's make-4.3-cloexec.patch, GCC 16.2.0, and -j64: without
> this change the warning appears and pigz runs with "-p 1"; with it there
> is no warning, and pigz runs with "-p 54" and "-p 64".
>
> Reported-by: Paul E. McKenney <paulmck@kernel.org>
> Closes: https://lore.kernel.org/all/0ddb5e5e-f801-444c-aa98-0cfe814a3026@paulmck-laptop/
> Fixes: 48ebe1cbbeb51 ("kbuild: compress the kernel with pigz if available")
> Assisted-by: LLM
> Signed-off-by: Kees Cook <kees@kernel.org>
Nice find!
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Sorry for breaking your build Paul ;)
--
Cheers, Lorenzo
next prev parent reply other threads:[~2026-10-09 12:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-09 6:27 [PATCH v1 0/2] kbuild: Give jobserver-exec recipes the jobserver Kees Cook
2026-10-09 6:27 ` [PATCH v1 1/2] kbuild: Mark the kernel image gzip recipes as recursive Kees Cook
2026-10-09 9:08 ` Nicolas Schier
2026-10-09 12:05 ` Lorenzo Stoakes (ARM) [this message]
2026-10-09 15:52 ` Paul E. McKenney
2026-10-09 15:51 ` Paul E. McKenney
2026-10-09 6:27 ` [PATCH v1 2/2] kbuild: Mark the initcall ordering recipe " Kees Cook
2026-10-09 15:20 ` Nicolas Schier
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