The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fc4cac4cfc437659ce445c3c47b807e1cc625b66 Mon Sep 17 00:00:00 2001

From: Alexander Lobakin alobakin@pm.me Date: Mon, 8 Feb 2021 12:37:42 +0000 Subject: [PATCH] MIPS: compressed: fix build with enabled UBSAN

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 := 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 Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de

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 := $(KBUILD_AFLAGS) -D__ASSEMBLY__ \ # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. KCOV_INSTRUMENT := n GCOV_PROFILE := n +UBSAN_SANITIZE := n

# decompressor objects (linked with vmlinuz) vmlinuzobjs-y := $(obj)/head.o $(obj)/decompress.o $(obj)/string.o