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smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tJWv7pYz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tJWv7pYz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52CDAC4CEEB; Tue, 16 Sep 2025 11:30:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758022226; bh=7AJ9SosdEk5i+W5nY4k1TcpdprbApX10Mjk/qkDMzKg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tJWv7pYzjnz9AgGz7GlLduVeiX96rkxfOM2efkdioY9vI3Ha+7F42iNpd/x0rdL8N NbzxzJNS+/ZkLGClPURCk4vLTgUKXKMbiUkl/cWOiZrBvDGYIzJewbLkwISd7pIIBD +DquBLYCy19dtblssKgBy1Ggp6r5agRf8D8Gly+dWR9axyOHY50se4fIaLupEk1PYz ibyJRZ5AEo29JXQ+vUaYuhqFZTH5sSk3OpnHxbeGKzNmGzMvUGfCiH1jqZpARuZwgt 8Jc479DR9Q+/YVfDQB9sah/GXh83vBStGxf9OErB3Z41IvtGnd9rhwUKxR+ZATGfQM MWijYO5zuuyIg== Date: Tue, 16 Sep 2025 13:30:20 +0200 From: Alexey Gladkov To: Nicolas Schier Cc: Nathan Chancellor , Petr Pavlu , Luis Chamberlain , Sami Tolvanen , Daniel Gomez , linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, linux-kbuild@vger.kernel.org, Masahiro Yamada Subject: Re: [PATCH v7 3/8] kbuild: keep .modinfo section in vmlinux.unstripped Message-ID: References: <4d53c72293d88b663257a0d723ebf3473a08b374.1755535876.git.legion@kernel.org> Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Sep 16, 2025 at 11:36:54AM +0200, Nicolas Schier wrote: > On Tue, Sep 16, 2025 at 09:12:22AM +0200, Alexey Gladkov wrote: > > On Mon, Sep 15, 2025 at 07:56:16AM +0200, Nicolas Schier wrote: > > > On Mon, Aug 18, 2025 at 06:54:57PM +0200, Alexey Gladkov wrote: > > > > From: Masahiro Yamada > > > > > > > > Keep the .modinfo section during linking, but strip it from the final > > > > vmlinux. > > > > > > > > Adjust scripts/mksysmap to exclude modinfo symbols from kallsyms. > > > > > > > > This change will allow the next commit to extract the .modinfo section > > > > from the vmlinux.unstripped intermediate. > > > > > > > > Signed-off-by: Masahiro Yamada > > > > --- > > > > include/asm-generic/vmlinux.lds.h | 2 +- > > > > scripts/Makefile.vmlinux | 2 +- > > > > scripts/mksysmap | 3 +++ > > > > 3 files changed, 5 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > > > > index ae2d2359b79e9..cfa63860dfd4c 100644 > > > > --- a/include/asm-generic/vmlinux.lds.h > > > > +++ b/include/asm-generic/vmlinux.lds.h > > > > @@ -831,6 +831,7 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG) > > > > > > > > /* Required sections not related to debugging. */ > > > > #define ELF_DETAILS \ > > > > + .modinfo : { *(.modinfo) } \ > > > > .comment 0 : { *(.comment) } \ > > > > .symtab 0 : { *(.symtab) } \ > > > > .strtab 0 : { *(.strtab) } \ > > > > @@ -1044,7 +1045,6 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG) > > > > *(.discard.*) \ > > > > *(.export_symbol) \ > > > > *(.no_trim_symbol) \ > > > > - *(.modinfo) \ > > > > /* ld.bfd warns about .gnu.version* even when not emitted */ \ > > > > *(.gnu.version*) \ > > > > > > > > diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux > > > > index 4f2d4c3fb7372..e2ceeb9e168d4 100644 > > > > --- a/scripts/Makefile.vmlinux > > > > +++ b/scripts/Makefile.vmlinux > > > > @@ -86,7 +86,7 @@ endif > > > > # vmlinux > > > > # --------------------------------------------------------------------------- > > > > > > > > -remove-section-y := > > > > +remove-section-y := .modinfo > > > > remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) += '.rel*' > > > > > > > > quiet_cmd_strip_relocs = OBJCOPY $@ > > > > diff --git a/scripts/mksysmap b/scripts/mksysmap > > > > index 3accbdb269ac7..a607a0059d119 100755 > > > > --- a/scripts/mksysmap > > > > +++ b/scripts/mksysmap > > > > @@ -79,6 +79,9 @@ > > > > / _SDA_BASE_$/d > > > > / _SDA2_BASE_$/d > > > > > > > > +# MODULE_INFO() > > > > +/ __UNIQUE_ID_modinfo[0-9]*$/d > > > > + > > > > # --------------------------------------------------------------------------- > > > > # Ignored patterns > > > > # (symbols that contain the pattern are ignored) > > > > -- > > > > 2.50.1 > > > > > > > > > > Hi Alexey, > > > > > > with this patch applied, I still get a warning from objcpy as Masahiro > > > and Stephen wrote [1,2] > > > > > > SORTTAB vmlinux.unstripped > > > + sorttable vmlinux.unstripped > > > + nm -S vmlinux.unstripped > > > + ./scripts/sorttable -s .tmp_vmlinux.nm-sort vmlinux.unstripped > > > + is_enabled CONFIG_KALLSYMS > > > + grep -q ^CONFIG_KALLSYMS=y include/config/auto.conf > > > + cmp -s System.map .tmp_vmlinux2.syms > > > + echo vmlinux.unstripped: ../scripts/link-vmlinux.sh > > > # OBJCOPY vmlinux > > > objcopy --remove-section=.modinfo vmlinux.unstripped vmlinux > > > objcopy: vmlinux.unstripped: warning: empty loadable segment detected at vaddr=0xffff8000807a0000, is this intentional? > > > > > > (arm64, allnoconfig) > > > > > > Kind regards, > > > Nicolas > > > > > > > > > [1]: https://lore.kernel.org/linux-kbuild/CAK7LNAR-gD2H6Kk-rZjo0R3weTHCGTm0a=u2tRH1WWW6Sx6=RQ@mail.gmail.com/ > > > [2]: https://lore.kernel.org/lkml/20250730164047.7c4a731a@canb.auug.org.au/ > > > > > > > Hm. I missed that. I need to investigate how to fix this. Nothing comes > > to mind right now. > > Same here. Only thing I could find until now is > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/diff/scripts/link-vmlinux.sh?id=90ceddcb495008ac8ba7a3dce297841efcd7d584 > > where '2>/dev/null' is appended exactly to prevent this very warning. > But for me, it doesn't feel good doing that when stripping to vmlinux. Yes, that's not a very good approach. It will hide other errors that will definitely need to be seen. I think the commit you mentioned is actually incorrect. I think there should be a different solution. I think in the case of .modinfo, we can change the flag in the section since we are going to delete it anyway. diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux index dbbe3bf0cf23..9a118b31d0dc 100644 --- a/scripts/Makefile.vmlinux +++ b/scripts/Makefile.vmlinux @@ -87,7 +87,8 @@ remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) += '.rel*' remove-symbols := -w --strip-symbol='__mod_device_table__*' quiet_cmd_strip_relocs = OBJCOPY $@ - cmd_strip_relocs = $(OBJCOPY) $(addprefix --remove-section=,$(remove-section-y)) \ + cmd_strip_relocs = $(OBJCOPY) $(patsubst %,--set-section-flags %=noload,$(remove-section-y)) $< && \ + $(OBJCOPY) $(addprefix --remove-section=,$(remove-section-y)) \ $(remove-symbols) $< $@ targets += vmlinux -- Rgrds, legion