Commit 0ebba714 authored by Marco Elver's avatar Marco Elver Committed by Paul E. McKenney
Browse files

build, kcsan: Add KCSAN build exceptions 



This blacklists several compilation units from KCSAN. See the respective
inline comments for the reasoning.

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 5f5c9712

drivers/firmware/efi/libstub/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -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

kernel/Makefile

+5 −0
Original line number Diff line number Diff line
@@ -23,6 +23,9 @@ endif 
# Prevents flicker of uninteresting __do_softirq()/__local_bh_disable_ip()

# in coverage traces.

KCOV_INSTRUMENT_softirq.o := n

# Avoid KCSAN instrumentation in softirq ("No shared variables, all the data

# are CPU local" => assume no data races), to reduce overhead in interrupts.

KCSAN_SANITIZE_softirq.o = n

# These are called from save_stack_trace() on slub debug path,

# and produce insane amounts of uninteresting coverage.

KCOV_INSTRUMENT_module.o := n
@@ -30,6 +33,7 @@ KCOV_INSTRUMENT_extable.o := n 
# Don't self-instrument.

KCOV_INSTRUMENT_kcov.o := n

KASAN_SANITIZE_kcov.o := n

KCSAN_SANITIZE_kcov.o := n

CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)



# cond_syscall is currently not LTO compatible
@@ -118,6 +122,7 @@ obj-$(CONFIG_RSEQ) += rseq.o 


obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o

KASAN_SANITIZE_stackleak.o := n

KCSAN_SANITIZE_stackleak.o := n

KCOV_INSTRUMENT_stackleak.o := n



$(obj)/configs.o: $(obj)/config_data.gz

kernel/sched/Makefile

+6 −0
Original line number Diff line number Diff line
@@ -7,6 +7,12 @@ endif 
# that is not a function of syscall inputs. E.g. involuntary context switches.

KCOV_INSTRUMENT := n



# There are numerous races here, however, most of them due to plain accesses.

# This would make it even harder for syzbot to find reproducers, because these

# bugs trigger without specific input. Disable by default, but should re-enable

# eventually.

KCSAN_SANITIZE := n



ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)

# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is

# needed for x86 only.  Why this used to be enabled for all architectures is beyond

mm/Makefile

+8 −0
Original line number Diff line number Diff line
@@ -7,6 +7,14 @@ KASAN_SANITIZE_slab_common.o := n 
KASAN_SANITIZE_slab.o := n

KASAN_SANITIZE_slub.o := n



# These produce frequent data race reports: most of them are due to races on

# the same word but accesses to different bits of that word. Re-enable KCSAN

# for these when we have more consensus on what to do about them.

KCSAN_SANITIZE_slab_common.o := n

KCSAN_SANITIZE_slab.o := n

KCSAN_SANITIZE_slub.o := n

KCSAN_SANITIZE_page_alloc.o := n



# These files are disabled because they produce non-interesting and/or

# flaky coverage that is not a function of syscall inputs. E.g. slab is out of

# free pages, or a task is migrated between nodes.