On Tue, Dec 14, 2021 at 05:20:31PM +0100, Alexander Potapenko wrote: > Instrumenting some files with KMSAN will result in kernel being unable > to link, boot or crashing at runtime for various reasons (e.g. infinite > recursion caused by instrumentation hooks calling instrumented code again). > > Completely omit KMSAN instrumentation in the following places: > - arch/x86/boot and arch/x86/realmode/rm, as KMSAN doesn't work for i386; > - arch/x86/entry/vdso, which isn't linked with KMSAN runtime; > - three files in arch/x86/kernel - boot problems; > - arch/x86/mm/cpu_entry_area.c - recursion; > - EFI stub - build failures; > - kcov, stackdepot, lockdep - recursion. It probably makes sense to split the arch/x86/ bits from everything else, and to group the arch/x86 enablement patches together closer to the end of the series. The non-x86 changes all look fine to me. Mark. > > Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> > --- > Link: https://linux-review.googlesource.com/id/Id5e5c4a9f9d53c24a35ebb633b814c414628d81b > --- > arch/x86/boot/Makefile | 1 + > arch/x86/boot/compressed/Makefile | 1 + > arch/x86/entry/vdso/Makefile | 3 +++ > arch/x86/kernel/Makefile | 2 ++ > arch/x86/kernel/cpu/Makefile | 1 + > arch/x86/mm/Makefile | 2 ++ > arch/x86/realmode/rm/Makefile | 1 + > drivers/firmware/efi/libstub/Makefile | 1 + > kernel/Makefile | 1 + > kernel/locking/Makefile | 3 ++- > lib/Makefile | 1 + > 11 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile > index b5aecb524a8aa..d5623232b763f 100644 > --- a/arch/x86/boot/Makefile > +++ b/arch/x86/boot/Makefile > @@ -12,6 +12,7 @@ > # Sanitizer runtimes are unavailable and cannot be linked for early boot code. > KASAN_SANITIZE := n > KCSAN_SANITIZE := n > +KMSAN_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 431bf7f846c3c..c4a284b738e71 100644 > --- a/arch/x86/boot/compressed/Makefile > +++ b/arch/x86/boot/compressed/Makefile > @@ -20,6 +20,7 @@ > # Sanitizer runtimes are unavailable and cannot be linked for early boot code. > KASAN_SANITIZE := n > KCSAN_SANITIZE := n > +KMSAN_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 a2dddcc189f69..f2a175d872b07 100644 > --- a/arch/x86/entry/vdso/Makefile > +++ b/arch/x86/entry/vdso/Makefile > @@ -11,6 +11,9 @@ include $(srctree)/lib/vdso/Makefile > > # Sanitizer runtimes are unavailable and cannot be linked here. > KASAN_SANITIZE := n > +KMSAN_SANITIZE_vclock_gettime.o := n > +KMSAN_SANITIZE_vgetcpu.o := n > + > UBSAN_SANITIZE := n > KCSAN_SANITIZE := n > OBJECT_FILES_NON_STANDARD := y > diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile > index 2ff3e600f4269..0b9fc3ecce2de 100644 > --- a/arch/x86/kernel/Makefile > +++ b/arch/x86/kernel/Makefile > @@ -35,6 +35,8 @@ KASAN_SANITIZE_cc_platform.o := n > # With some compiler versions the generated code results in boot hangs, caused > # by several compilation units. To be safe, disable all instrumentation. > KCSAN_SANITIZE := n > +KMSAN_SANITIZE_head$(BITS).o := n > +KMSAN_SANITIZE_nmi.o := n > > OBJECT_FILES_NON_STANDARD_test_nx.o := y > > diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile > index 9661e3e802be5..f10a921ee7565 100644 > --- a/arch/x86/kernel/cpu/Makefile > +++ b/arch/x86/kernel/cpu/Makefile > @@ -12,6 +12,7 @@ endif > # If these files are instrumented, boot hangs during the first second. > KCOV_INSTRUMENT_common.o := n > KCOV_INSTRUMENT_perf_event.o := n > +KMSAN_SANITIZE_common.o := n > > # As above, instrumenting secondary CPU boot code causes boot hangs. > KCSAN_SANITIZE_common.o := n > diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile > index 5864219221ca8..747d4630d52ce 100644 > --- a/arch/x86/mm/Makefile > +++ b/arch/x86/mm/Makefile > @@ -10,6 +10,8 @@ KASAN_SANITIZE_mem_encrypt_identity.o := n > # Disable KCSAN entirely, because otherwise we get warnings that some functions > # reference __initdata sections. > KCSAN_SANITIZE := n > +# Avoid recursion by not calling KMSAN hooks for CEA code. > +KMSAN_SANITIZE_cpu_entry_area.o := n > > ifdef CONFIG_FUNCTION_TRACER > CFLAGS_REMOVE_mem_encrypt.o = -pg > diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile > index 83f1b6a56449f..f614009d3e4e2 100644 > --- a/arch/x86/realmode/rm/Makefile > +++ b/arch/x86/realmode/rm/Makefile > @@ -10,6 +10,7 @@ > # Sanitizer runtimes are unavailable and cannot be linked here. > KASAN_SANITIZE := n > KCSAN_SANITIZE := n > +KMSAN_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 d0537573501e9..81432d0c904b1 100644 > --- a/drivers/firmware/efi/libstub/Makefile > +++ b/drivers/firmware/efi/libstub/Makefile > @@ -46,6 +46,7 @@ GCOV_PROFILE := n > # Sanitizer runtimes are unavailable and cannot be linked here. > KASAN_SANITIZE := n > KCSAN_SANITIZE := n > +KMSAN_SANITIZE := n > UBSAN_SANITIZE := n > OBJECT_FILES_NON_STANDARD := y > > diff --git a/kernel/Makefile b/kernel/Makefile > index 186c49582f45b..e5dd600e63d8a 100644 > --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -39,6 +39,7 @@ KCOV_INSTRUMENT_kcov.o := n > KASAN_SANITIZE_kcov.o := n > KCSAN_SANITIZE_kcov.o := n > UBSAN_SANITIZE_kcov.o := n > +KMSAN_SANITIZE_kcov.o := n > CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector > > # Don't instrument error handlers > diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile > index d51cabf28f382..ea925731fa40f 100644 > --- a/kernel/locking/Makefile > +++ b/kernel/locking/Makefile > @@ -5,8 +5,9 @@ KCOV_INSTRUMENT := n > > obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o > > -# Avoid recursion lockdep -> KCSAN -> ... -> lockdep. > +# Avoid recursion lockdep -> sanitizer -> ... -> lockdep. > KCSAN_SANITIZE_lockdep.o := n > +KMSAN_SANITIZE_lockdep.o := n > > ifdef CONFIG_FUNCTION_TRACER > CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE) > diff --git a/lib/Makefile b/lib/Makefile > index 364c23f155781..8e5ae9d5966de 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -268,6 +268,7 @@ obj-$(CONFIG_IRQ_POLL) += irq_poll.o > CFLAGS_stackdepot.o += -fno-builtin > obj-$(CONFIG_STACKDEPOT) += stackdepot.o > KASAN_SANITIZE_stackdepot.o := n > +KMSAN_SANITIZE_stackdepot.o := n > KCOV_INSTRUMENT_stackdepot.o := n > > libfdt_files = fdt.o fdt_ro.o fdt_wip.o fdt_rw.o fdt_sw.o fdt_strerror.o \ > -- > 2.34.1.173.g76aa8bc2d0-goog >
