From: Marco Elver <[email protected]> commit 33cd65e73abd693c00c4156cf23677c453b41b3b upstream.
During early boot, while KASAN is not yet initialized, it is possible to enter reporting code-path and end up in kasan_report(). While uninitialized, the branch there prevents generating any reports, however, under certain circumstances when branches are being traced (TRACE_BRANCH_PROFILING), we may recurse deep enough to cause kernel reboots without warning. To prevent similar issues in future, we should disable branch tracing for the core runtime. [[email protected]: remove duplicate DISABLE_BRANCH_PROFILING, per Qian Cai] Link: https://lore.kernel.org/lkml/20200517011732.GE24705@shao2-debian/ Link: http://lkml.kernel.org/r/[email protected] Reported-by: kernel test robot <[email protected]> Signed-off-by: Marco Elver <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Reviewed-by: Andrey Konovalov <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: Alexander Potapenko <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Qian Cai <[email protected]> Cc: <[email protected]> Link: http://lkml.kernel.org/r//20200517011732.GE24705@shao2-debian/ Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/kasan/Makefile | 8 ++++---- mm/kasan/generic.c | 1 - mm/kasan/tags.c | 1 - 3 files changed, 4 insertions(+), 6 deletions(-) --- a/mm/kasan/Makefile +++ b/mm/kasan/Makefile @@ -14,10 +14,10 @@ CFLAGS_REMOVE_tags.o = $(CC_FLAGS_FTRACE # Function splitter causes unnecessary splits in __asan_load1/__asan_store1 # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533 -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_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) +CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING +CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING +CFLAGS_generic_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING +CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING obj-$(CONFIG_KASAN) := common.o init.o report.o obj-$(CONFIG_KASAN_GENERIC) += generic.o generic_report.o quarantine.o --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -15,7 +15,6 @@ */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -#define DISABLE_BRANCH_PROFILING #include <linux/export.h> #include <linux/interrupt.h> --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -12,7 +12,6 @@ */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -#define DISABLE_BRANCH_PROFILING #include <linux/export.h> #include <linux/interrupt.h>
