[PATCH 4.9 19/43] vmlinux.lds.h: Handle clang's module.{c,d}tor sections

From: Sasha Levin
Date: Tue Aug 24 2021 - 13:37:00 EST

From: Nathan Chancellor <nathan@xxxxxxxxxx>

commit 848378812e40152abe9b9baf58ce2004f76fb988 upstream.

A recent change in LLVM causes module_{c,d}tor sections to appear when
CONFIG_K{A,C}SAN are enabled, which results in orphan section warnings
because these are not handled anywhere:

ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.asan.module_ctor) is being placed in '.text.asan.module_ctor'
ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.asan.module_dtor) is being placed in '.text.asan.module_dtor'
ld.lld: warning: arch/x86/pci/built-in.a(legacy.o):(.text.tsan.module_ctor) is being placed in '.text.tsan.module_ctor'

Fangrui explains: "the function asan.module_ctor has the SHF_GNU_RETAIN
flag, so it is in a separate section even with -fno-function-sections

Place them in the TEXT_TEXT section so that these technologies continue
to work with the newer compiler versions. All of the KASAN and KCSAN
KUnit tests continue to pass after this change.

Cc: stable@xxxxxxxxxxxxxxx
Link: https://github.com/ClangBuiltLinux/linux/issues/1432
Link: https://github.com/llvm/llvm-project/commit/7b789562244ee941b7bf2cefeb3fc08a59a01865
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reviewed-by: Fangrui Song <maskray@xxxxxxxxxx>
Acked-by: Marco Elver <elver@xxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210731023107.1932981-1-nathan@xxxxxxxxxx
[nc: Fix conflicts due to lack of cf68fffb66d60 and 266ff2a8f51f0]
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
include/asm-generic/vmlinux.lds.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 36198563fb8b..8cff6d157e56 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -465,6 +465,7 @@
*(.text.unlikely .text.unlikely.*) \
*(.text.unknown .text.unknown.*) \
*(.ref.text) \
+ *(.text.asan.* .text.tsan.*) \
MEM_KEEP(init.text) \
MEM_KEEP(exit.text) \