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Date:   Mon, 08 Feb 2021 12:37:42 +0000
To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
From:   Alexander Lobakin <alobakin@pm.me>
Cc:     Paul Cercueil <paul@crapouillou.net>,
        Alexander Lobakin <alobakin@pm.me>,
        Youling Tang <tangyouling@loongson.cn>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Xingxing Su <suxingxing@loongson.cn>,
        Huacai Chen <chenhuacai@kernel.org>,
        Paul Burton <paulburton@kernel.org>,
        Hassan Naveed <hnaveed@wavecomp.com>,
        linux-mips@vger.kernel.org, stable@vger.kernel.org,
        linux-kernel@vger.kernel.org
Reply-To: Alexander Lobakin <alobakin@pm.me>
Subject: [PATCH mips-fixes] MIPS: compressed: fix build with enabled UBSAN
Message-ID: <20210208123645.101354-1-alobakin@pm.me>
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Precedence: bulk

Commit 1e35918ad9d1 ("MIPS: Enable Undefined Behavior Sanitizer
UBSAN") added a possibility to build the entire kernel with UBSAN
instrumentation for MIPS, with the exception for VDSO.
However, self-extracting head wasn't been added to exceptions, so
this occurs:

mips-alpine-linux-musl-ld: arch/mips/boot/compressed/decompress.o:
in function `FSE_buildDTable_wksp':
decompress.c:(.text.FSE_buildDTable_wksp+0x278): undefined reference
to `__ubsan_handle_shift_out_of_bounds'
mips-alpine-linux-musl-ld: decompress.c:(.text.FSE_buildDTable_wksp+0x2a8):
undefined reference to `__ubsan_handle_shift_out_of_bounds'
mips-alpine-linux-musl-ld: decompress.c:(.text.FSE_buildDTable_wksp+0x2c4):
undefined reference to `__ubsan_handle_shift_out_of_bounds'
mips-alpine-linux-musl-ld: arch/mips/boot/compressed/decompress.o:
decompress.c:(.text.FSE_buildDTable_raw+0x9c): more undefined references
to `__ubsan_handle_shift_out_of_bounds' follow

Add UBSAN_SANITIZE :=3D n to mips/boot/compressed/Makefile to exclude
it from instrumentation scope and fix this issue.

Fixes: 1e35918ad9d1 ("MIPS: Enable Undefined Behavior Sanitizer UBSAN")
Cc: stable@vger.kernel.org # 5.0+
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 arch/mips/boot/compressed/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed=
/Makefile
index 47cd9dc7454a..f93f72bcba97 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -37,6 +37,7 @@ KBUILD_AFLAGS :=3D $(KBUILD_AFLAGS) -D__ASSEMBLY__ \
 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
 KCOV_INSTRUMENT=09=09:=3D n
 GCOV_PROFILE :=3D n
+UBSAN_SANITIZE :=3D n
=20
 # decompressor objects (linked with vmlinuz)
 vmlinuzobjs-y :=3D $(obj)/head.o $(obj)/decompress.o $(obj)/string.o
--=20
2.30.0