From db547ef1906400eb34682e43035dd4d81b9fdcfb Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 15 Jun 2016 17:45:47 +0200 Subject: Kbuild: don't add obj tree in additional includes When building with separate object directories and driver specific Makefiles that add additional header include paths, Kbuild adjusts the gcc flags so that we include both the directory in the source tree and in the object tree. However, due to another bug I fixed earlier, this did not actually include the correct directory in the object tree, so we know that we only really need the source tree here. Also, including the object tree sometimes causes warnings about nonexisting directories when the include path only exists in the source. This changes the logic to only emit the -I argument for the srctree, not for objects. We still need both $(srctree)/$(src) and $(obj) though, so I'm adding them manually. Signed-off-by: Arnd Bergmann Signed-off-by: Michal Marek --- scripts/Makefile.lib | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'scripts/Makefile.lib') diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index e7df0f5db7ec..e89c214745eb 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -155,9 +155,10 @@ else # $(call addtree,-I$(obj)) locates .h files in srctree, from generated .c files # and locates generated .h files # FIXME: Replace both with specific CFLAGS* statements in the makefiles -__c_flags = $(call addtree,-I$(obj)) $(call flags,_c_flags) -__a_flags = $(call flags,_a_flags) -__cpp_flags = $(call flags,_cpp_flags) +__c_flags = $(if $(obj),-I$(srctree)/$(src) -I$(obj)) \ + $(call flags,_c_flags) +__a_flags = $(call flags,_a_flags) +__cpp_flags = $(call flags,_cpp_flags) endif c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \ -- cgit v1.2.3 From a4691deabf284a601149a067525759939cc563b2 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Tue, 2 Aug 2016 14:07:30 -0700 Subject: kcov: allow more fine-grained coverage instrumentation For more targeted fuzzing, it's better to disable kernel-wide instrumentation and instead enable it on a per-subsystem basis. This follows the pattern of UBSAN and allows you to compile in the kcov driver without instrumenting the whole kernel. To instrument a part of the kernel, you can use either # for a single file in the current directory KCOV_INSTRUMENT_filename.o := y or # for all the files in the current directory (excluding subdirectories) KCOV_INSTRUMENT := y or # (same as above) ccflags-y += $(CFLAGS_KCOV) or # for all the files in the current directory (including subdirectories) subdir-ccflags-y += $(CFLAGS_KCOV) Link: http://lkml.kernel.org/r/1464008380-11405-1-git-send-email-vegard.nossum@oracle.com Signed-off-by: Vegard Nossum Cc: Dmitry Vyukov Cc: Quentin Casasnovas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.debug | 11 +++++++++++ scripts/Makefile.lib | 2 +- 2 files changed, 12 insertions(+), 1 deletion(-) (limited to 'scripts/Makefile.lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index f07842e2d69f..cc02f282d05b 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -719,6 +719,17 @@ config KCOV For more details, see Documentation/kcov.txt. +config KCOV_INSTRUMENT_ALL + bool "Instrument all code by default" + depends on KCOV + default y if KCOV + help + If you are doing generic system call fuzzing (like e.g. syzkaller), + then you will want to instrument the whole kernel and you should + say y here. If you are doing more targeted fuzzing (like e.g. + filesystem fuzzing with AFL) then you will want to enable coverage + for more specific subsets of files, and should say n here. + config DEBUG_SHIRQ bool "Debug shared IRQ handlers" depends on DEBUG_KERNEL diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index e7df0f5db7ec..76494e15417b 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -138,7 +138,7 @@ endif ifeq ($(CONFIG_KCOV),y) _c_flags += $(if $(patsubst n%,, \ - $(KCOV_INSTRUMENT_$(basetarget).o)$(KCOV_INSTRUMENT)y), \ + $(KCOV_INSTRUMENT_$(basetarget).o)$(KCOV_INSTRUMENT)$(CONFIG_KCOV_INSTRUMENT_ALL)), \ $(CFLAGS_KCOV)) endif -- cgit v1.2.3