From 0d345996e4cb573f8cc81d49b3ee9a7fd2035bef Mon Sep 17 00:00:00 2001 From: Pengfei Xu Date: Mon, 31 Jul 2023 11:04:18 +0800 Subject: [PATCH] x86/kernel: increase kcov coverage under arch/x86/kernel folder Currently kcov instrument is disabled for object files under arch/x86/kernel folder. For object files under arch/x86/kernel, actually just disabling the kcov instrument of files:"head32.o or head64.o and sev.o" could achieve successful booting and provide kcov coverage for object files that do not disable kcov instrument. The additional kcov coverage collected from arch/x86/kernel folder helps kernel fuzzing efforts to find bugs. Link to related improvement discussion is below: https://groups.google.com/g/syzkaller/c/Dsl-RYGCqs8/m/x-tfpTyFBAAJ Related ticket is as follow: https://bugzilla.kernel.org/show_bug.cgi?id=198443 Link: https://lkml.kernel.org/r/06c0bb7b5f61e5884bf31180e8c122648c752010.1690771380.git.pengfei.xu@intel.com Reviewed-by: Dmitry Vyukov Tested-by: Dmitry Vyukov Signed-off-by: Pengfei Xu Cc: Aleksandr Nogikh Cc: Cc: Ingo Molnar Cc: Kees Cook , Cc: Kirill A. Shutemov Cc: Sohil Mehta Signed-off-by: Andrew Morton --- arch/x86/kernel/Makefile | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 4070a01..00df34c 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -33,11 +33,10 @@ KCSAN_SANITIZE := n KMSAN_SANITIZE_head$(BITS).o := n KMSAN_SANITIZE_nmi.o := n -# If instrumentation of this dir is enabled, boot hangs during first second. -# Probably could be more selective here, but note that files related to irqs, -# boot, dumpstack/stacktrace, etc are either non-interesting or can lead to -# non-deterministic coverage. -KCOV_INSTRUMENT := n +# If instrumentation of the following files is enabled, boot hangs during +# first second. +KCOV_INSTRUMENT_head$(BITS).o := n +KCOV_INSTRUMENT_sev.o := n CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace -- 2.7.4