From: Marco Elver <elver@google.com>
To: elver@google.com
Cc: dvyukov@google.com, glider@google.com, andreyknvl@google.com,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
aryabinin@virtuozzo.com, akpm@linux-foundation.org,
linux-mm@kvack.org, cai@lca.pw,
kernel test robot <rong.a.chen@intel.com>
Subject: [PATCH v2] kasan: Disable branch tracing for core runtime
Date: Fri, 22 May 2020 09:52:07 +0200 [thread overview]
Message-ID: <20200522075207.157349-1-elver@google.com> (raw)
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.
Link: https://lore.kernel.org/lkml/20200517011732.GE24705@shao2-debian/
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Marco Elver <elver@google.com>
---
v2:
* Remove duplicate DISABLE_BRANCH_PROFILING from tags.c as reported by
Qian Cai.
---
mm/kasan/Makefile | 16 ++++++++--------
mm/kasan/generic.c | 1 -
mm/kasan/tags.c | 1 -
3 files changed, 8 insertions(+), 10 deletions(-)
diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index 434d503a6525..de3121848ddf 100644
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -15,14 +15,14 @@ CFLAGS_REMOVE_tags_report.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_init.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
-CFLAGS_quarantine.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)
-CFLAGS_tags_report.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_init.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING
+CFLAGS_quarantine.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -DDISABLE_BRANCH_PROFILING
+CFLAGS_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
+CFLAGS_tags_report.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
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 56ff8885fe2e..098a7dbaced6 100644
--- 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>
diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
index 25b7734e7013..8a959fdd30e3 100644
--- 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>
--
2.27.0.rc0.183.gde8f92d652-goog
next reply other threads:[~2020-05-22 7:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 7:52 Marco Elver [this message]
2020-05-22 23:42 ` [PATCH v2] kasan: Disable branch tracing for core runtime Andrew Morton
2020-05-23 9:12 ` Marco Elver
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