String functions can be useful in early boot, but using instrumented versions can be problematic: eg on x86, some of the early boot code is executing out of an identity mapping rather than the kernel virtual addresses. Accessing any global variables at this point will lead to a crash.
Tracing and KCOV are already disabled, and CONFIG_AMD_MEM_ENCRYPT will additionally disable KASAN and stack protector. Additionally disable GCOV, UBSAN, KCSAN, STACKLEAK_PLUGIN and branch profiling, and make it unconditional to allow safe use of string functions. Signed-off-by: Arvind Sankar <nived...@alum.mit.edu> --- lib/Makefile | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/lib/Makefile b/lib/Makefile index a4a4c6864f51..5e421769bbc6 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -8,7 +8,6 @@ ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE) # These files are disabled because they produce lots of non-interesting and/or # flaky coverage that is not a function of syscall inputs. For example, # rbtree can be global and individual rotations don't correlate with inputs. -KCOV_INSTRUMENT_string.o := n KCOV_INSTRUMENT_rbtree.o := n KCOV_INSTRUMENT_list_debug.o := n KCOV_INSTRUMENT_debugobjects.o := n @@ -20,12 +19,16 @@ KCOV_INSTRUMENT_fault-inject.o := n # them into calls to themselves. CFLAGS_string.o := -ffreestanding -# Early boot use of cmdline, don't instrument it -ifdef CONFIG_AMD_MEM_ENCRYPT +# Early boot use of string functions, disable instrumentation +GCOV_PROFILE_string.o := n +KCOV_INSTRUMENT_string.o := n KASAN_SANITIZE_string.o := n +UBSAN_SANITIZE_string.o := n +KCSAN_SANITIZE_string.o := n CFLAGS_string.o += -fno-stack-protector -endif +CFLAGS_string.o += $(DISABLE_STACKLEAK_PLUGIN) +CFLAGS_string.o += -DDISABLE_BRANCH_PROFILING # Used by KCSAN while enabled, avoid recursion. KCSAN_SANITIZE_random32.o := n -- 2.26.2
