Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux

kasan: disable branch tracing for core runtime

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.

[elver@google.com: remove duplicate DISABLE_BRANCH_PROFILING, per Qian Cai]
Link: https://lore.kernel.org/lkml/20200517011732.GE24705@shao2-debian/
Link: http://lkml.kernel.org/r/20200522075207.157349-1-elver@google.com
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r//20200517011732.GE24705@shao2-debian/
Link: http://lkml.kernel.org/r/20200519182459.87166-1-elver@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

authored by

Marco Elver and committed by
Linus Torvalds
33cd65e7 380e5c1d

+8 -10
+8 -8
mm/kasan/Makefile
··· 15 15 16 16 # Function splitter causes unnecessary splits in __asan_load1/__asan_store1 17 17 # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533 18 - CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) 19 - CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) 20 - CFLAGS_generic_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) 21 - CFLAGS_init.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) 22 - CFLAGS_quarantine.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) 23 - CFLAGS_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) 24 - CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) 25 - CFLAGS_tags_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) 18 + CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING 19 + CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING 20 + CFLAGS_generic_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING 21 + CFLAGS_init.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING 22 + CFLAGS_quarantine.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING 23 + CFLAGS_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING 24 + CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING 25 + CFLAGS_tags_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING 26 26 27 27 obj-$(CONFIG_KASAN) := common.o init.o report.o 28 28 obj-$(CONFIG_KASAN_GENERIC) += generic.o generic_report.o quarantine.o
-1
mm/kasan/generic.c
··· 15 15 */ 16 16 17 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 - #define DISABLE_BRANCH_PROFILING 19 18 20 19 #include <linux/export.h> 21 20 #include <linux/interrupt.h>
-1
mm/kasan/tags.c
··· 12 12 */ 13 13 14 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 - #define DISABLE_BRANCH_PROFILING 16 15 17 16 #include <linux/export.h> 18 17 #include <linux/interrupt.h>