Re: [Buildroot] [PATCH v2 2/2] linux: use -isystem instead of -I in HOSTCC

From: Francis Laniel <flaniel@linux.microsoft.com>
To: "buildroot@buildroot.org" <buildroot@buildroot.org>,
	Lang Daniel <d.lang@abatec.at>
Subject: Re: [Buildroot] [PATCH v2 2/2] linux: use -isystem instead of -I in HOSTCC
Date: Thu, 16 Feb 2023 15:48:37 +0100	[thread overview]
Message-ID: <4807202.31r3eYUQgx@pwmachine> (raw)
In-Reply-To: <12152275.O9o76ZdvQC@pwmachine>

Le jeudi 16 février 2023, 15:23:35 CET Francis Laniel a écrit :
> Hi.
> 
> Le mercredi 15 février 2023, 10:58:51 CET Lang Daniel a écrit :
> > A package might install headers that are incompatible with the kernel's
> > header. One example is the most recent version of pahole (1.24).
> > HOST_CC includes -I$(HOST_DIR)/include which comes before any include
> > logic the kernel might have thus forcing the kernel to prefer headers in
> > HOST_DIR.
> > 
> > The logic to substituting -I with -isystem is taken from
> > boot/uboot/uboot.mk.
> > 
> > Signed-off-by: Daniel Lang <d.lang@abatec.at>
> 
> Thank you for this patch!
> I tested it and got the same error as you:
> FAILED: load BTF from vmlinux: Invalid argument
> 
> I tested with qemu_x86_64_defconfig to which I added the same options as
> you. I will test with a kernel younger than 5.15.18 and I come back here!

I tested with latest kernel and everything works like a charm:
Welcome to Buildroot
buildroot login: root
# uname -r
6.1.11
# ls /sys/kernel/btf/
vmlinux
Thank you for it!

Reviewed-by: Francis Laniel <flaniel@linux.microsoft.com>
Tested-by: Francis Laniel <flaniel@linux.microsoft.com>

> > ---
> > 
> > v1 -> v2:
> >  - Patch was added to the series
> > 
> > Tested with:
> > 
> > BR2_aarch64=y
> > BR2_TOOLCHAIN_EXTERNAL=y
> > BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD=y
> > BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y
> > BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_AARCH64_GLIBC_STABLE=y
> > BR2_LINUX_KERNEL=y
> > BR2_LINUX_KERNEL_CUSTOM_VERSION=y
> > BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="{VERSION}"
> > BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG=y
> > BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="pahole-kernel.config"
> > BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
> > BR2_LINUX_KERNEL_NEEDS_HOST_PAHOLE=y
> > 
> > and with a fragment for linux:
> > 
> > CONFIG_BPF_SYSCALL=y
> > CONFIG_BPF_UNPRIV_DEFAULT_OFF=n
> > CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
> > CONFIG_DEBUG_INFO_REDUCED=n
> > CONFIG_DEBUG_INFO_COMPRESSED=n
> > CONFIG_DEBUG_INFO_BTF=y
> > CONFIG_SYSTEM_TRUSTED_KEYRING=y
> > 
> > where VERSION is one of:
> > 5.2.21 5.3.18 5.4.231 5.5.19 5.6.19 5.7.19 5.8.18 5.9.16 5.10.167 5.11.22
> > 5.12.19 5.13.19 5.14.21 5.15.93 5.16.20 5.17.15 5.18.19 5.19.17 6.0.19
> > 6.1.11
> > 
> > Version 5.2, as far as I could work it out, is the version that introduced
> > the pahole dependency when CONFIG_DEBUG_INFO_BTF is set.
> > 
> > None-LTS versions after 5.10 and before 5.19 fail with:
> >   LD      vmlinux.o
> >   MODPOST vmlinux.symvers
> >   MODINFO modules.builtin.modinfo
> >   GEN     modules.builtin
> >   LD      .tmp_vmlinux.btf
> >   BTF     .btf.vmlinux.bin.o
> >   LD      .tmp_vmlinux.kallsyms1
> >   KSYMS   .tmp_vmlinux.kallsyms1.S
> >   AS      .tmp_vmlinux.kallsyms1.S
> >   LD      .tmp_vmlinux.kallsyms2
> >   KSYMS   .tmp_vmlinux.kallsyms2.S
> >   AS      .tmp_vmlinux.kallsyms2.S
> >   LD      vmlinux
> >   BTFIDS  vmlinux
> > 
> > FAILED: load BTF from vmlinux: Invalid argument
> > make[2]: *** [Makefile:1177: vmlinux] Error 255
> > make[1]: *** [package/pkg-generic.mk:293:
> > /home/d.lang/ws/other/buildroot/output/build/linux-5.11.22/.stamp_built]
> > Error 2 make: *** [Makefile:82: _all] Error 2
> > 
> > These version miss BTF_KIND_ENUM64 support and require a patch [0] that
> > has
> > been added to LTS versions.
> > 
> > [0]:
> > https://lore.kernel.org/bpf/20221019085604.1017583-6-jolsa@kernel.org/
> > 
> > Signed-off-by: Daniel Lang <d.lang@abatec.at>
> > ---
> > 
> >  linux/linux.mk | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/linux/linux.mk b/linux/linux.mk
> > index 7645b5f507..03d89cd204 100644
> > --- a/linux/linux.mk
> > +++ b/linux/linux.mk
> > @@ -150,7 +150,7 @@ endif
> > 
> >  # Disable building host tools with -Werror: newer gcc versions can be
> >  # extra picky about some code
> > 
> > (https://bugs.busybox.net/show_bug.cgi?id=14826) LINUX_MAKE_FLAGS = \
> > -	HOSTCC="$(HOSTCC) $(HOST_CFLAGS) $(HOST_LDFLAGS)" \
> > +	HOSTCC="$(HOSTCC) $(subst -I/,-isystem /,$(subst -I /,-isystem
> > /,$(HOST_CFLAGS))) $(HOST_LDFLAGS)" \ ARCH=$(KERNEL_ARCH) \
> > 
> >  	INSTALL_MOD_PATH=$(TARGET_DIR) \
> >  	CROSS_COMPILE="$(TARGET_CROSS)" \
> 
> Best regards.

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