From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C88F11BC47; Thu, 22 Feb 2024 08:27:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708590455; cv=none; b=SUV9wP+JbxrVg7r8xbWxI4nHJaxD5ClGz221RKlWPuFCUjM14LAbisNP5ZGvSVPFn9oUpNBi2MWv3DS4Nwb5Dx+mlY18oXKaR32DmhPl8NifjPKLPJNmFgvRhAZX1Xm4utSTGI2LHGIgtkoazO9Z6YHdgR6Ujk5BbU0/NmNubjw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708590455; c=relaxed/simple; bh=p3VlxVj/5wDXjcpnhxerm7Qtm3/1EiqMF+SiT1FG7LM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=murW9/+U5i/I8U0fQLiqAwDjCsaRJ7m9Wtd3teDlhZWgM+kOEWodO2WgX2RYcxjy4TT8Cqiof2ptDl/8JyWgoPcCieCqz/Fl8mmBrjJKNZ1UCuXdEQkBm0KjjpZIG1/LGrNpgvu+OzB6XUepbQI/6RgkUVfOxAuUbFKLv2joH4A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zd/79A7k; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="zd/79A7k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A516CC433F1; Thu, 22 Feb 2024 08:27:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708590455; bh=p3VlxVj/5wDXjcpnhxerm7Qtm3/1EiqMF+SiT1FG7LM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=zd/79A7klRgyePIIDwFq15NRBqyM0vOTM6jk0rSa2WyXqOV/A3aFGtPNqlMRSeLwP c63/iiNRKizMkev3s/kxUljYmnHsB/84O2zN8HyX5hH+LH2AGO55cst5mvpzfFr/lP m5qIUc3FU91dkoCbrl9vOM6pywju4cGaACy2vi2o= Date: Thu, 22 Feb 2024 09:27:31 +0100 From: Greg Kroah-Hartman To: Nathan Chancellor Cc: stable@vger.kernel.org, patches@lists.linux.dev, Masahiro Yamada , Fangrui Song , Nicolas Schier , Kees Cook , Justin Stitt Subject: Re: [PATCH 5.15 380/476] kbuild: Fix changing ELF file type for output of gen_btf for big endian Message-ID: <2024022253-skewed-bobble-1d5c@gregkh> References: <20240221130007.738356493@linuxfoundation.org> <20240221130022.096353982@linuxfoundation.org> <20240221165424.GC1782141@dev-arch.thelio-3990X> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240221165424.GC1782141@dev-arch.thelio-3990X> On Wed, Feb 21, 2024 at 09:54:24AM -0700, Nathan Chancellor wrote: > Hi Greg, > > On Wed, Feb 21, 2024 at 02:07:11PM +0100, Greg Kroah-Hartman wrote: > > 5.15-stable review patch. If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Nathan Chancellor > > > > commit e3a9ee963ad8ba677ca925149812c5932b49af69 upstream. > > > > Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > > changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works > > fine for little endian platforms: > > > > 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > > > However, for big endian platforms, it changes the wrong byte, resulting > > in an invalid ELF file type, which ld.lld rejects: > > > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > > > Type: : 103 > > > > ld.lld: error: .btf.vmlinux.bin.o: unknown file type > > > > Fix this by updating the entire 16-bit e_type field rather than just a > > single byte, so that everything works correctly for all platforms and > > linkers. > > > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > > > Type: REL (Relocatable file) > > > > While in the area, update the comment to mention that binutils 2.35+ > > matches LLD's behavior of rejecting an ET_EXEC input, which occurred > > after the comment was added. > > > > Cc: stable@vger.kernel.org > > Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > > Link: https://github.com/llvm/llvm-project/pull/75643 > > Suggested-by: Masahiro Yamada > > Signed-off-by: Nathan Chancellor > > Reviewed-by: Fangrui Song > > Reviewed-by: Nicolas Schier > > Reviewed-by: Kees Cook > > Reviewed-by: Justin Stitt > > Signed-off-by: Masahiro Yamada > > Signed-off-by: Greg Kroah-Hartman > > --- > > scripts/link-vmlinux.sh | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > --- a/scripts/link-vmlinux.sh > > +++ b/scripts/link-vmlinux.sh > > @@ -236,8 +236,13 @@ gen_btf() > > ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ > > --strip-all ${1} ${2} 2>/dev/null > > # Change e_type to ET_REL so that it can be used to link final vmlinux. > > - # Unlike GNU ld, lld does not allow an ET_EXEC input. > > - printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none > > + # GNU ld 2.35+ and lld do not allow an ET_EXEC input. > > + if is_enabled CONFIG_CPU_BIG_ENDIAN; then > > You may have missed my mail on the email saying this had been applied (I > didn't cc a lore list so no link): Ick, I did get it but it got lost in the shuffle, my fault. > I do not think this backport is correct for trees that do not have > commit 7d153696e5db ("kbuild: do not include include/config/auto.conf > from shell scripts"), even if it applies cleanly, as is_enabled() is not > available. > > I think this diff should be squashed in to the patch for 5.15 and > earlier, you can add > > [nathan: Fix silent conflict due to lack of 7d153696e5db in older trees] > Signed-off-by: Nathan Chancellor > > to the resulting patch if you would like. I'll go add that now, thanks for catching this! greg k-h