On Mon, Jun 3, 2019 at 11:11 AM Anders Roxell <anders.roxell@xxxxxxxxxx> wrote: > > __kasan_report() triggers ftrace and the preempt_count() in ftrace > causes a call to __asan_load4(), breaking the circular dependency by > making report as no trace for ftrace. > > Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx> > --- > mm/kasan/Makefile | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile > index 08b43de2383b..2b2da731483c 100644 > --- a/mm/kasan/Makefile > +++ b/mm/kasan/Makefile > @@ -3,12 +3,14 @@ KASAN_SANITIZE := n > UBSAN_SANITIZE_common.o := n > UBSAN_SANITIZE_generic.o := n > UBSAN_SANITIZE_generic_report.o := n > +UBSAN_SANITIZE_report.o := n > UBSAN_SANITIZE_tags.o := n > KCOV_INSTRUMENT := n > > CFLAGS_REMOVE_common.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_generic.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_generic_report.o = $(CC_FLAGS_FTRACE) > +CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_tags.o = $(CC_FLAGS_FTRACE) > > # Function splitter causes unnecessary splits in __asan_load1/__asan_store1 > @@ -17,6 +19,7 @@ CFLAGS_REMOVE_tags.o = $(CC_FLAGS_FTRACE) > CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > CFLAGS_generic_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > +CFLAGS_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > obj-$(CONFIG_KASAN) := common.o init.o report.o Acked-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Is it needed in all section? Or you just followed the pattern? Different flag changes were initially done on very specific files for specific reasons. E.g. -fno-conserve-stack is only for performance reasons, so report* should not be there. But I see Peter already added generic_report.o there. Perhaps we need to give up on selective per-file changes, because this causes constant flow of new bugs in the absence of testing and just do something like: KASAN_SANITIZE := n KCOV_INSTRUMENT := n UBSAN_SANITIZE := n CFLAGS_REMOVE = $(CC_FLAGS_FTRACE) CFLAGS := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
