| Message ID | 20191017141305.146193-9-elver@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add Kernel Concurrency Sanitizer (KCSAN) | expand |
On Thu, Oct 17, 2019 at 04:13:05PM +0200, Marco Elver wrote: > This patch enables KCSAN for x86, with updates to build rules to not use > KCSAN for several incompatible compilation units. > > Signed-off-by: Marco Elver <elver@google.com> > --- > v2: > * Document build exceptions where no previous above comment explained > why we cannot instrument. > --- > arch/x86/Kconfig | 1 + > arch/x86/boot/Makefile | 2 ++ > arch/x86/boot/compressed/Makefile | 2 ++ > arch/x86/entry/vdso/Makefile | 3 +++ > arch/x86/include/asm/bitops.h | 6 +++++- > arch/x86/kernel/Makefile | 7 +++++++ > arch/x86/kernel/cpu/Makefile | 3 +++ > arch/x86/lib/Makefile | 4 ++++ > arch/x86/mm/Makefile | 3 +++ > arch/x86/purgatory/Makefile | 2 ++ > arch/x86/realmode/Makefile | 3 +++ > arch/x86/realmode/rm/Makefile | 3 +++ > drivers/firmware/efi/libstub/Makefile | 2 ++ > 13 files changed, 40 insertions(+), 1 deletion(-) > diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile > index 0460c7581220..693d0a94b118 100644 > --- a/drivers/firmware/efi/libstub/Makefile > +++ b/drivers/firmware/efi/libstub/Makefile > @@ -31,7 +31,9 @@ KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ > -D__DISABLE_EXPORTS > > GCOV_PROFILE := n > +# Sanitizer runtimes are unavailable and cannot be linked here. > KASAN_SANITIZE := n > +KCSAN_SANITIZE := n > UBSAN_SANITIZE := n > OBJECT_FILES_NON_STANDARD := y Not a big deal, but it might make sense to move the EFI stub exception to patch 3 since it isn't x86 specific (and will also apply for arm64). Otherwise this looks good to me. Thanks, Mark.
On Tue, 22 Oct 2019 at 14:59, Mark Rutland <mark.rutland@arm.com> wrote: > > On Thu, Oct 17, 2019 at 04:13:05PM +0200, Marco Elver wrote: > > This patch enables KCSAN for x86, with updates to build rules to not use > > KCSAN for several incompatible compilation units. > > > > Signed-off-by: Marco Elver <elver@google.com> > > --- > > v2: > > * Document build exceptions where no previous above comment explained > > why we cannot instrument. > > --- > > arch/x86/Kconfig | 1 + > > arch/x86/boot/Makefile | 2 ++ > > arch/x86/boot/compressed/Makefile | 2 ++ > > arch/x86/entry/vdso/Makefile | 3 +++ > > arch/x86/include/asm/bitops.h | 6 +++++- > > arch/x86/kernel/Makefile | 7 +++++++ > > arch/x86/kernel/cpu/Makefile | 3 +++ > > arch/x86/lib/Makefile | 4 ++++ > > arch/x86/mm/Makefile | 3 +++ > > arch/x86/purgatory/Makefile | 2 ++ > > arch/x86/realmode/Makefile | 3 +++ > > arch/x86/realmode/rm/Makefile | 3 +++ > > drivers/firmware/efi/libstub/Makefile | 2 ++ > > 13 files changed, 40 insertions(+), 1 deletion(-) > > > diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile > > index 0460c7581220..693d0a94b118 100644 > > --- a/drivers/firmware/efi/libstub/Makefile > > +++ b/drivers/firmware/efi/libstub/Makefile > > @@ -31,7 +31,9 @@ KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ > > -D__DISABLE_EXPORTS > > > > GCOV_PROFILE := n > > +# Sanitizer runtimes are unavailable and cannot be linked here. > > KASAN_SANITIZE := n > > +KCSAN_SANITIZE := n > > UBSAN_SANITIZE := n > > OBJECT_FILES_NON_STANDARD := y > > Not a big deal, but it might make sense to move the EFI stub exception > to patch 3 since it isn't x86 specific (and will also apply for arm64). Thanks for spotting, moved for v3. -- Marco > Otherwise this looks good to me. > > Thanks, > Mark.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index d6e1faa28c58..81859be4a005 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -226,6 +226,7 @@ config X86 select VIRT_TO_BUS select X86_FEATURE_NAMES if PROC_FS select PROC_PID_ARCH_STATUS if PROC_FS + select HAVE_ARCH_KCSAN if X86_64 config INSTRUCTION_DECODER def_bool y diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index e2839b5c246c..9c7942794164 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -9,7 +9,9 @@ # Changed by many, many contributors over the years. # +# Sanitizer runtimes are unavailable and cannot be linked for early boot code. KASAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Kernel does not boot with kcov instrumentation here. diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 6b84afdd7538..a1c248b8439f 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -17,7 +17,9 @@ # (see scripts/Makefile.lib size_append) # compressed vmlinux.bin.all + u32 size of vmlinux.bin.all +# Sanitizer runtimes are unavailable and cannot be linked for early boot code. KASAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 0f2154106d01..a23debaad5b9 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -10,8 +10,11 @@ ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE include $(srctree)/lib/vdso/Makefile KBUILD_CFLAGS += $(DISABLE_LTO) + +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n UBSAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h index 7d1f6a49bfae..ee08917d3d92 100644 --- a/arch/x86/include/asm/bitops.h +++ b/arch/x86/include/asm/bitops.h @@ -201,8 +201,12 @@ arch_test_and_change_bit(long nr, volatile unsigned long *addr) return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc), *addr, c, "Ir", nr); } -static __always_inline bool constant_test_bit(long nr, const volatile unsigned long *addr) +static __no_kcsan_or_inline bool constant_test_bit(long nr, const volatile unsigned long *addr) { + /* + * Because this is a plain access, we need to disable KCSAN here to + * avoid double instrumentation via bitops-instrumented.h. + */ return ((1UL << (nr & (BITS_PER_LONG-1))) & (addr[nr >> _BITOPS_LONG_SHIFT])) != 0; } diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 3578ad248bc9..2aa122d94956 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -28,6 +28,13 @@ KASAN_SANITIZE_dumpstack_$(BITS).o := n KASAN_SANITIZE_stacktrace.o := n KASAN_SANITIZE_paravirt.o := n +# Do not instrument early boot code. +KCSAN_SANITIZE_head$(BITS).o := n +# Do not instrument debug code to avoid corrupting bug reporting. +KCSAN_SANITIZE_dumpstack.o := n +KCSAN_SANITIZE_dumpstack_$(BITS).o := n +KCSAN_SANITIZE_stacktrace.o := n + OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y OBJECT_FILES_NON_STANDARD_test_nx.o := y OBJECT_FILES_NON_STANDARD_paravirt_patch.o := y diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index d7a1e5a9331c..1f1b0edc0187 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -13,6 +13,9 @@ endif KCOV_INSTRUMENT_common.o := n KCOV_INSTRUMENT_perf_event.o := n +# As above, instrumenting secondary CPU boot code causes boot hangs. +KCSAN_SANITIZE_common.o := n + # Make sure load_percpu_segment has no stackprotector nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_common.o := $(nostackp) diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 5246db42de45..432a07705677 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -6,10 +6,14 @@ # Produces uninteresting flaky coverage. KCOV_INSTRUMENT_delay.o := n +# KCSAN uses udelay for introducing watchpoint delay; avoid recursion. +KCSAN_SANITIZE_delay.o := n + # Early boot use of cmdline; don't instrument it ifdef CONFIG_AMD_MEM_ENCRYPT KCOV_INSTRUMENT_cmdline.o := n KASAN_SANITIZE_cmdline.o := n +KCSAN_SANITIZE_cmdline.o := n ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_cmdline.o = -pg diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index 84373dc9b341..ee871602f96a 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile @@ -7,6 +7,9 @@ KCOV_INSTRUMENT_mem_encrypt_identity.o := n KASAN_SANITIZE_mem_encrypt.o := n KASAN_SANITIZE_mem_encrypt_identity.o := n +KCSAN_SANITIZE_mem_encrypt.o := n +KCSAN_SANITIZE_mem_encrypt_identity.o := n + ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_mem_encrypt.o = -pg CFLAGS_REMOVE_mem_encrypt_identity.o = -pg diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index fb4ee5444379..69379bce9574 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -17,7 +17,9 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib targets += purgatory.ro +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n KCOV_INSTRUMENT := n # These are adjustments to the compiler flags used for objects that diff --git a/arch/x86/realmode/Makefile b/arch/x86/realmode/Makefile index 682c895753d9..6b1f3a4eeb44 100644 --- a/arch/x86/realmode/Makefile +++ b/arch/x86/realmode/Makefile @@ -6,7 +6,10 @@ # for more details. # # + +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y subdir- := rm diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile index f60501a384f9..fdbbb945c216 100644 --- a/arch/x86/realmode/rm/Makefile +++ b/arch/x86/realmode/rm/Makefile @@ -6,7 +6,10 @@ # for more details. # # + +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 0460c7581220..693d0a94b118 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -31,7 +31,9 @@ KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ -D__DISABLE_EXPORTS GCOV_PROFILE := n +# Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KCSAN_SANITIZE := n UBSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y
This patch enables KCSAN for x86, with updates to build rules to not use KCSAN for several incompatible compilation units. Signed-off-by: Marco Elver <elver@google.com> --- v2: * Document build exceptions where no previous above comment explained why we cannot instrument. --- arch/x86/Kconfig | 1 + arch/x86/boot/Makefile | 2 ++ arch/x86/boot/compressed/Makefile | 2 ++ arch/x86/entry/vdso/Makefile | 3 +++ arch/x86/include/asm/bitops.h | 6 +++++- arch/x86/kernel/Makefile | 7 +++++++ arch/x86/kernel/cpu/Makefile | 3 +++ arch/x86/lib/Makefile | 4 ++++ arch/x86/mm/Makefile | 3 +++ arch/x86/purgatory/Makefile | 2 ++ arch/x86/realmode/Makefile | 3 +++ arch/x86/realmode/rm/Makefile | 3 +++ drivers/firmware/efi/libstub/Makefile | 2 ++ 13 files changed, 40 insertions(+), 1 deletion(-)