From nobody Tue Dec 16 12:36:53 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57FB2C4332F for ; Thu, 13 Oct 2022 17:52:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229739AbiJMRw4 (ORCPT ); Thu, 13 Oct 2022 13:52:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229560AbiJMRwu (ORCPT ); Thu, 13 Oct 2022 13:52:50 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ECB2214FD34; Thu, 13 Oct 2022 10:52:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5742A618F7; Thu, 13 Oct 2022 17:52:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2934EC433C1; Thu, 13 Oct 2022 17:52:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1665683567; bh=ib1lQCV01pXW8JO0BmnZksOwhGMo3P498BUfkCHG5/U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XVDC6UKUI7MjyaU5NMvDqjmIHvRW5vvSmZoWjcGHrpNP7CIctJRN6vv1zjJID1Vqi hPPmRNPPmlUq41jvOZDQtdGImf07cl2LXOxiNf+gW3fROxUolu1Pgq/eyNvMEsF1FR 2z3Q0CpZ7Kcqap4ZhYrsosiZd+Ag1vivAV3Mu23Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Gow , Lukas Straub , Richard Weinberger , Sasha Levin , Randy Dunlap Subject: [PATCH 5.4 12/38] arch: um: Mark the stack non-executable to fix a binutils warning Date: Thu, 13 Oct 2022 19:52:13 +0200 Message-Id: <20221013175144.682353616@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221013175144.245431424@linuxfoundation.org> References: <20221013175144.245431424@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: David Gow [ Upstream commit bd71558d585ac61cfd799db7f25e78dca404dd7a ] Since binutils 2.39, ld will print a warning if any stack section is executable, which is the default for stack sections on files without a .note.GNU-stack section. This was fixed for x86 in commit ffcf9c5700e4 ("x86: link vdso and boot wit= h -z noexecstack --no-warn-rwx-segments"), but remained broken for UML, resulting in several warnings: /usr/bin/ld: warning: arch/x86/um/vdso/vdso.o: missing .note.GNU-stack sect= ion implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a fu= ture version of the linker /usr/bin/ld: warning: .tmp_vmlinux.kallsyms1 has a LOAD segment with RWX pe= rmissions /usr/bin/ld: warning: .tmp_vmlinux.kallsyms1.o: missing .note.GNU-stack sec= tion implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a fu= ture version of the linker /usr/bin/ld: warning: .tmp_vmlinux.kallsyms2 has a LOAD segment with RWX pe= rmissions /usr/bin/ld: warning: .tmp_vmlinux.kallsyms2.o: missing .note.GNU-stack sec= tion implies executable stack /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a fu= ture version of the linker /usr/bin/ld: warning: vmlinux has a LOAD segment with RWX permissions Link both the VDSO and vmlinux with -z noexecstack, fixing the warnings about .note.GNU-stack sections. In addition, pass --no-warn-rwx-segments to dodge the remaining warnings about LOAD segments with RWX permissions in the kallsyms objects. (Note that this flag is apparently not available on lld, so hide it behind a test for BFD, which is what the x86 patch does.) Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/co= mmit/?id=3Dffcf9c5700e49c0aee42dcba9a12ba21338e8136 Link: https://sourceware.org/git/?p=3Dbinutils-gdb.git;a=3Dcommit;h=3Dba951= afb99912da01a6e8434126b8fac7aa75107 Signed-off-by: David Gow Reviewed-by: Lukas Straub Tested-by: Lukas Straub Acked-by: Randy Dunlap # build-tested Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/Makefile | 8 ++++++++ arch/x86/um/vdso/Makefile | 2 +- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/um/Makefile b/arch/um/Makefile index 275f5ffdf6f0..773120be0f56 100644 --- a/arch/um/Makefile +++ b/arch/um/Makefile @@ -132,10 +132,18 @@ export LDS_ELF_FORMAT :=3D $(ELF_FORMAT) # The wrappers will select whether using "malloc" or the kernel allocator. LINK_WRAPS =3D -Wl,--wrap,malloc -Wl,--wrap,free -Wl,--wrap,calloc =20 +# Avoid binutils 2.39+ warnings by marking the stack non-executable and +# ignorning warnings for the kallsyms sections. +LDFLAGS_EXECSTACK =3D -z noexecstack +ifeq ($(CONFIG_LD_IS_BFD),y) +LDFLAGS_EXECSTACK +=3D $(call ld-option,--no-warn-rwx-segments) +endif + LD_FLAGS_CMDLINE =3D $(foreach opt,$(KBUILD_LDFLAGS),-Wl,$(opt)) =20 # Used by link-vmlinux.sh which has special support for um link export CFLAGS_vmlinux :=3D $(LINK-y) $(LINK_WRAPS) $(LD_FLAGS_CMDLINE) +export LDFLAGS_vmlinux :=3D $(LDFLAGS_EXECSTACK) =20 # When cleaning we don't include .config, so we don't include # TT or skas makefiles and don't clean skas_ptregs.h. diff --git a/arch/x86/um/vdso/Makefile b/arch/x86/um/vdso/Makefile index 0caddd6acb22..bec115036f87 100644 --- a/arch/x86/um/vdso/Makefile +++ b/arch/x86/um/vdso/Makefile @@ -62,7 +62,7 @@ quiet_cmd_vdso =3D VDSO $@ -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \ sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@' =20 -VDSO_LDFLAGS =3D -fPIC -shared -Wl,--hash-style=3Dsysv +VDSO_LDFLAGS =3D -fPIC -shared -Wl,--hash-style=3Dsysv -z noexecstack GCOV_PROFILE :=3D n =20 # --=20 2.35.1