kcsan: Disable branch tracing in core runtime

Disable branch tracing in core KCSAN runtime if branches are being traced (TRACE_BRANCH_PROFILING). This it to avoid its performance impact, but also avoid recursion in case KCSAN is enabled for the branch tracing runtime. The latter had already been a problem for KASAN: https://lore.kernel.org/lkml/CANpmjNOeXmD5E3O50Z3MjkiuCYaYOPyi+1rq=GZvEKwBvLR0Ug@mail.gmail.com/ Signed-off-by: Marco Elver <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]>
torvalds · Jun 29, 2020 · 61d56d7 · 61d56d7
1 parent 2839a23
commit 61d56d7
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/kernel/kcsan/Makefile b/kernel/kcsan/Makefile
@@ -8,7 +8,7 @@ CFLAGS_REMOVE_debugfs.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE)
 
 CFLAGS_core.o := $(call cc-option,-fno-conserve-stack) \
-	-fno-stack-protector
+	-fno-stack-protector -DDISABLE_BRANCH_PROFILING
 
 obj-y := core.o debugfs.o report.o
 obj-$(CONFIG_KCSAN_SELFTEST) += selftest.o