While __noinstr already contained __no_sanitize_coverage, it needs to
be added to __init and __head section markings to support the Clang
implementation of CONFIG_KSTACK_ERASE. This is to make sure the stack
depth tracking callback is not executed in unsupported contexts.
The other sanitizer coverage options (trace-pc and trace-cmp) aren't
needed in __head nor __init either ("We are interested in code coverage
as a function of a syscall inputs"[1]), so this is fine to disable for
them as well.
Link:
https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/kcov.c?h=v6.14#n179
[1]
Acked-by: Marco Elver <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
---
Cc: Marco Elver <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Hou Wenlong <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: "Peter Zijlstra (Intel)" <[email protected]>
Cc: Luis Chamberlain <[email protected]>
Cc: Sami Tolvanen <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: <[email protected]>
---
arch/x86/include/asm/init.h | 2 +-
include/linux/init.h | 4 +++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/init.h b/arch/x86/include/asm/init.h
index 8b1b1abcef15..6bfdaeddbae8 100644
--- a/arch/x86/include/asm/init.h
+++ b/arch/x86/include/asm/init.h
@@ -5,7 +5,7 @@
#if defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 170000
#define __head __section(".head.text") __no_sanitize_undefined
__no_stack_protector
#else
-#define __head __section(".head.text") __no_sanitize_undefined
+#define __head __section(".head.text") __no_sanitize_undefined
__no_sanitize_coverage
#endif
struct x86_mapping_info {
diff --git a/include/linux/init.h b/include/linux/init.h
index ee1309473bc6..c65a050d52a7 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -49,7 +49,9 @@
/* These are for everybody (although not all archs will actually
discard it in modules) */
-#define __init __section(".init.text") __cold __latent_entropy
__noinitretpoline
+#define __init __section(".init.text") __cold __latent_entropy \
+ __noinitretpoline \
+ __no_sanitize_coverage
#define __initdata __section(".init.data")
#define __initconst __section(".init.rodata")
#define __exitdata __section(".exit.data")
--
2.34.1
