[PATCH 1/2] x86/tools/relocs: Fix non-POSIX regexp

From: "H. Nikolaus Schaller" <hns@goldelico.com>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, Jessica Yu <jeyu@kernel.org>,
	Miroslav Benes <mbenes@suse.cz>,
	Emil Velikov <emil.l.velikov@gmail.com>,
	Nick Desaulniers <ndesaulniers@google.com>
Cc: letux-kernel@openphoenux.org, "H. Peter Anvin" <hpa@zytor.com>,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel@pyra-handheld.com,
	"H. Nikolaus Schaller" <hns@goldelico.com>
Subject: [PATCH 1/2] x86/tools/relocs: Fix non-POSIX regexp
Date: Thu,  8 Jul 2021 10:57:09 +0200	[thread overview]
Message-ID: <81c6de380d932bfb94d96fb70459dd47afd6ed5d.1625734629.git.hns@goldelico.com> (raw)
In-Reply-To: <cover.1625734629.git.hns@goldelico.com>

Trying to run a cross-compiled x86 relocs tool on a BSD based
HOSTCC leads to errors like

  VOFFSET arch/x86/boot/compressed/../voffset.h - due to: vmlinux
  CC      arch/x86/boot/compressed/misc.o - due to: arch/x86/boot/compressed/../voffset.h
  OBJCOPY arch/x86/boot/compressed/vmlinux.bin - due to: vmlinux
  RELOCS  arch/x86/boot/compressed/vmlinux.relocs - due to: vmlinux
empty (sub)expressionarch/x86/boot/compressed/Makefile:118: recipe for target 'arch/x86/boot/compressed/vmlinux.relocs' failed
make[3]: *** [arch/x86/boot/compressed/vmlinux.relocs] Error 1

It turns out that relocs.c uses patterns like

	"something(|_end)"

This is not valid syntax or gives undefined results according
to POSIX 9.5.3 ERE Grammar

	https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html

It seems to be silently accepted by the Linux regexp() implementation
while a BSD host complains.

Such patterns can be replaced by a transformation like

	"(|p1|p2)" -> "(p1|p2)?"

Fixes: fd952815307f ("x86-32, relocs: Whitelist more symbols for ld bug workaround")
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
---
 arch/x86/tools/relocs.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 04c5a44b96827..9ba700dc47de4 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -57,12 +57,12 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	[S_REL] =
 	"^(__init_(begin|end)|"
 	"__x86_cpu_dev_(start|end)|"
-	"(__parainstructions|__alt_instructions)(|_end)|"
-	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
+	"(__parainstructions|__alt_instructions)(_end)?|"
+	"(__iommu_table|__apicdrivers|__smp_locks)(_end)?|"
 	"__(start|end)_pci_.*|"
 	"__(start|end)_builtin_fw|"
-	"__(start|stop)___ksymtab(|_gpl)|"
-	"__(start|stop)___kcrctab(|_gpl)|"
+	"__(start|stop)___ksymtab(_gpl)?|"
+	"__(start|stop)___kcrctab(_gpl)?|"
 	"__(start|stop)___param|"
 	"__(start|stop)___modver|"
 	"__(start|stop)___bug_table|"
-- 
2.31.1

