Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37;
MIME-Version: 1.0
References: <20231119053448.2367725-1-masahiroy@kernel.org>
In-Reply-To: <20231119053448.2367725-1-masahiroy@kernel.org>
From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Sun, 19 Nov 2023 19:59:11 +0800
Message-ID: <CAAhV-H6Y4vqc45eaMs+wCN7Quf4e9ogp8aDA8V0sA=TUnMWd-Q@mail.gmail.com>
Subject: Re: [PATCH] loongarch: add dependency between vmlinuz.efi and vmlinux.efi
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     WANG Xuerui <kernel@xen0n.name>, loongarch@lists.linux.dev,
        linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
        Ard Biesheuvel <ardb@kernel.org>,
        Simon Glass <sjg@chromium.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Hi, Masahiro,

On Sun, Nov 19, 2023 at 1:35=E2=80=AFPM Masahiro Yamada <masahiroy@kernel.o=
rg> wrote:
>
> A common issue in Makefile is a race in parallel building.
>
> You need to be careful to prevent multiple threads from writing to the
> same file simultaneously.
>
> Commit 3939f3345050 ("ARM: 8418/1: add boot image dependencies to not
> generate invalid images") addressed such a bad scenario.
>
> A similar symptom occurs with the following command:
>
>   $ make -j$(nproc) ARCH=3Dloongarch vmlinux.efi vmlinuz.efi
>     [ snip ]
>     SORTTAB vmlinux
>     OBJCOPY arch/loongarch/boot/vmlinux.efi
>     OBJCOPY arch/loongarch/boot/vmlinux.efi
>     PAD     arch/loongarch/boot/vmlinux.bin
>     GZIP    arch/loongarch/boot/vmlinuz
>     OBJCOPY arch/loongarch/boot/vmlinuz.o
>     LD      arch/loongarch/boot/vmlinuz.efi.elf
>     OBJCOPY arch/loongarch/boot/vmlinuz.efi
>
> The log "OBJCOPY arch/loongarch/boot/vmlinux.efi" is displayed twice.
>
> It indicates that two threads simultaneously enter arch/loongarch/boot/
> and write to arch/loongarch/boot/vmlinux.efi.
>
> It occasionally leads to a build failure:
>
>   $ make -j$(nproc) ARCH=3Dloongarch vmlinux.efi vmlinuz.efi
>     [ snip ]
>     SORTTAB vmlinux
>     OBJCOPY arch/loongarch/boot/vmlinux.efi
>     PAD     arch/loongarch/boot/vmlinux.bin
>   truncate: Invalid number: =E2=80=98arch/loongarch/boot/vmlinux.bin=E2=
=80=99
>   make[2]: *** [drivers/firmware/efi/libstub/Makefile.zboot:13:
>   arch/loongarch/boot/vmlinux.bin] Error 1
>   make[2]: *** Deleting file 'arch/loongarch/boot/vmlinux.bin'
>   make[1]: *** [arch/loongarch/Makefile:146: vmlinuz.efi] Error 2
>   make[1]: *** Waiting for unfinished jobs....
>   make: *** [Makefile:234: __sub-make] Error 2
>
> vmlinuz.efi depends on vmlinux.efi, but such a dependency is not
> specified in arch/loongarch/Makefile.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
>
>  arch/loongarch/Makefile | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
> index 9eeb0c05f3f4..6022bf3d30c9 100644
> --- a/arch/loongarch/Makefile
> +++ b/arch/loongarch/Makefile
> @@ -142,6 +142,7 @@ vdso-install-y +=3D arch/loongarch/vdso/vdso.so.dbg
>
>  all:   $(notdir $(KBUILD_IMAGE))
>
> +vmlinuz.efi: vmlinux.efi
>  vmlinux.elf vmlinux.efi vmlinuz.efi: vmlinux
>         $(Q)$(MAKE) $(build)=3D$(boot) $(bootvars-y) $(boot)/$@
It is a little strange, because

in drivers/firmware/efi/libstub/Makefile.zboot:
vmlinuz.efi depends on vmlinuz.efi.elf, vmlinuz.efi.elf depends on
vmlinuz.o, vmlinuz.o depends on vmlinuz, vmlinuz depends on
vmlinux.bin, vmlinux.bin depends on $(EFI_ZBOOT_PAYLOAD).

in arch/loongarch/boot/Makefile,
EFI_ZBOOT_PAYLOAD :=3D vmlinux.efi

So I think vmlinuz.efi has already depend on vmlinux.efi.

Huacai

>
> --
> 2.40.1
>
>