Commit dfd402a4 authored by Marco Elver's avatar Marco Elver Committed by Paul E. McKenney
Browse files

kcsan: Add Kernel Concurrency Sanitizer infrastructure 



Kernel Concurrency Sanitizer (KCSAN) is a dynamic data-race detector for
kernel space. KCSAN is a sampling watchpoint-based data-race detector.
See the included Documentation/dev-tools/kcsan.rst for more details.

This patch adds basic infrastructure, but does not yet enable KCSAN for
any architecture.

Signed-off-by: default avatarMarco Elver <elver@google.com>
Acked-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 31f4f5b4

MAINTAINERS

+11 −0
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@@ -8848,6 +8848,17 @@ F: Documentation/kbuild/kconfig* 
F:	scripts/kconfig/

F:	scripts/Kconfig.include









KCSAN









M:	Marco Elver <elver@google.com>









R:	Dmitry Vyukov <dvyukov@google.com>









L:	kasan-dev@googlegroups.com









S:	Maintained









F:	Documentation/dev-tools/kcsan.rst









F:	include/linux/kcsan*.h









F:	kernel/kcsan/









F:	lib/Kconfig.kcsan









F:	scripts/Makefile.kcsan

















KDUMP









M:	Dave Young <dyoung@redhat.com>









M:	Baoquan He <bhe@redhat.com>


































Makefile



+2
−1






























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@@ -478,7 +478,7 @@ export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE

















export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS









export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE









export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN









export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN CFLAGS_KCSAN









export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE









export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE









export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL










@@ -900,6 +900,7 @@ endif







include scripts/Makefile.kasan









include scripts/Makefile.extrawarn









include scripts/Makefile.ubsan









include scripts/Makefile.kcsan



















# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments









KBUILD_CPPFLAGS += $(KCPPFLAGS)


































include/linux/compiler-clang.h



+9
−0






























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@@ -24,6 +24,15 @@







#define __no_sanitize_address









#endif



















#if __has_feature(thread_sanitizer)









/* emulate gcc's __SANITIZE_THREAD__ flag */









#define __SANITIZE_THREAD__









#define __no_sanitize_thread \









		__attribute__((no_sanitize("thread")))









#else









#define __no_sanitize_thread









#endif



















/*









 * Not all versions of clang implement the the type-generic versions









 * of the builtin overflow checkers. Fortunately, clang implements


































include/linux/compiler-gcc.h



+7
−0






























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@@ -145,6 +145,13 @@







#define __no_sanitize_address









#endif



















#if defined(__SANITIZE_THREAD__) && __has_attribute(__no_sanitize_thread__)









#define __no_sanitize_thread                                                   \









	__attribute__((__noinline__)) __attribute__((no_sanitize_thread))









#else









#define __no_sanitize_thread









#endif



















#if GCC_VERSION >= 50100









#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1









#endif


































include/linux/compiler.h



+29
−8






























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@@ -178,6 +178,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,







#endif



















#include <uapi/linux/types.h>









#include <linux/kcsan-checks.h>



















#define __READ_ONCE_SIZE						\









({									\










@@ -193,12 +194,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,







	}								\









})



















static __always_inline









void __read_once_size(const volatile void *p, void *res, int size)









{









	__READ_ONCE_SIZE;









}



















#ifdef CONFIG_KASAN









/*









 * We can't declare function 'inline' because __no_sanitize_address confilcts










@@ -207,18 +202,44 @@ void __read_once_size(const volatile void *p, void *res, int size)







 * '__maybe_unused' allows us to avoid defined-but-not-used warnings.









 */









# define __no_kasan_or_inline __no_sanitize_address notrace __maybe_unused









# define __no_sanitize_or_inline __no_kasan_or_inline









#else









# define __no_kasan_or_inline __always_inline









#endif



















static __no_kasan_or_inline









#ifdef __SANITIZE_THREAD__









/*









 * Rely on __SANITIZE_THREAD__ instead of CONFIG_KCSAN, to avoid not inlining in









 * compilation units where instrumentation is disabled.









 */









# define __no_kcsan_or_inline __no_sanitize_thread notrace __maybe_unused









# define __no_sanitize_or_inline __no_kcsan_or_inline









#else









# define __no_kcsan_or_inline __always_inline









#endif



















#ifndef __no_sanitize_or_inline









#define __no_sanitize_or_inline __always_inline









#endif



















static __no_kcsan_or_inline









void __read_once_size(const volatile void *p, void *res, int size)









{









	kcsan_check_atomic_read(p, size);









	__READ_ONCE_SIZE;









}



















static __no_sanitize_or_inline









void __read_once_size_nocheck(const volatile void *p, void *res, int size)









{









	__READ_ONCE_SIZE;









}



















static __always_inline void __write_once_size(volatile void *p, void *res, int size)









static __no_kcsan_or_inline









void __write_once_size(volatile void *p, void *res, int size)









{









	kcsan_check_atomic_write(p, size);



















	switch (size) {









	case 1: *(volatile __u8 *)p = *(__u8 *)res; break;









	case 2: *(volatile __u16 *)p = *(__u16 *)res; break;