From 43e76af85fa7e75ac9b71fc2fcc250abb1889bff Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Thu, 30 Jan 2020 22:17:35 -0800 Subject: kcov: ignore fault-inject and stacktrace Don't instrument 3 more files that contain debugging facilities and produce large amounts of uninteresting coverage for every syscall. The following snippets are sprinkled all over the place in kcov traces in a debugging kernel. We already try to disable instrumentation of stack unwinding code and of most debug facilities. I guess we did not use fault-inject.c at the time, and stacktrace.c was somehow missed (or something has changed in kernel/configs). This change both speeds up kcov (kernel doesn't need to store these PCs, user-space doesn't need to process them) and frees trace buffer capacity for more useful coverage. should_fail lib/fault-inject.c:149 fail_dump lib/fault-inject.c:45 stack_trace_save kernel/stacktrace.c:124 stack_trace_consume_entry kernel/stacktrace.c:86 stack_trace_consume_entry kernel/stacktrace.c:89 ... a hundred frames skipped ... stack_trace_consume_entry kernel/stacktrace.c:93 stack_trace_consume_entry kernel/stacktrace.c:86 Link: http://lkml.kernel.org/r/20200116111449.217744-1-dvyukov@gmail.com Signed-off-by: Dmitry Vyukov Reviewed-by: Andrey Konovalov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/Makefile | 1 + 1 file changed, 1 insertion(+) (limited to 'mm') diff --git a/mm/Makefile b/mm/Makefile index 1937cc251883..32f08e22e824 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -20,6 +20,7 @@ KCOV_INSTRUMENT_kmemleak.o := n KCOV_INSTRUMENT_memcontrol.o := n KCOV_INSTRUMENT_mmzone.o := n KCOV_INSTRUMENT_vmstat.o := n +KCOV_INSTRUMENT_failslab.o := n CFLAGS_init-mm.o += $(call cc-disable-warning, override-init) CFLAGS_init-mm.o += $(call cc-disable-warning, initializer-overrides) -- cgit v1.2.3-59-g8ed1b