* [PATCH] kasan: Disable branch tracing for core runtime
@ 2020-05-19 18:24 Marco Elver
2020-05-19 21:05 ` Andrey Konovalov
2020-05-21 22:11 ` Qian Cai
0 siblings, 2 replies; 5+ messages in thread
From: Marco Elver @ 2020-05-19 18:24 UTC (permalink / raw)
To: elver
Cc: dvyukov, glider, andreyknvl, linux-kernel, kasan-dev, aryabinin,
akpm, linux-mm, kernel test robot
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>
---
mm/kasan/Makefile | 16 ++++++++--------
mm/kasan/generic.c | 1 -
2 files changed, 8 insertions(+), 9 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>
--
2.26.2.761.g0e0b3e54be-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] kasan: Disable branch tracing for core runtime
2020-05-19 18:24 [PATCH] kasan: Disable branch tracing for core runtime Marco Elver
@ 2020-05-19 21:05 ` Andrey Konovalov
2020-05-20 0:09 ` Andrew Morton
2020-05-21 22:11 ` Qian Cai
1 sibling, 1 reply; 5+ messages in thread
From: Andrey Konovalov @ 2020-05-19 21:05 UTC (permalink / raw)
To: Marco Elver
Cc: Dmitry Vyukov, Alexander Potapenko, LKML, kasan-dev,
Andrey Ryabinin, Andrew Morton, Linux Memory Management List,
kernel test robot
On Tue, May 19, 2020 at 8:25 PM Marco Elver <elver@google.com> wrote:
>
> 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>
> ---
> mm/kasan/Makefile | 16 ++++++++--------
> mm/kasan/generic.c | 1 -
> 2 files changed, 8 insertions(+), 9 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>
> --
> 2.26.2.761.g0e0b3e54be-goog
>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Thanks!
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] kasan: Disable branch tracing for core runtime
2020-05-19 21:05 ` Andrey Konovalov
@ 2020-05-20 0:09 ` Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2020-05-20 0:09 UTC (permalink / raw)
To: Andrey Konovalov
Cc: Marco Elver, Dmitry Vyukov, Alexander Potapenko, LKML, kasan-dev,
Andrey Ryabinin, Linux Memory Management List, kernel test robot
On Tue, 19 May 2020 23:05:46 +0200 Andrey Konovalov <andreyknvl@google.com> wrote:
> On Tue, May 19, 2020 at 8:25 PM Marco Elver <elver@google.com> wrote:
> >
> > 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.
> >
>
> ...
>
> Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Thanks, I queued this for 5.7.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] kasan: Disable branch tracing for core runtime
2020-05-19 18:24 [PATCH] kasan: Disable branch tracing for core runtime Marco Elver
2020-05-19 21:05 ` Andrey Konovalov
@ 2020-05-21 22:11 ` Qian Cai
2020-05-22 7:54 ` Marco Elver
1 sibling, 1 reply; 5+ messages in thread
From: Qian Cai @ 2020-05-21 22:11 UTC (permalink / raw)
To: Marco Elver
Cc: dvyukov, glider, andreyknvl, linux-kernel, kasan-dev, aryabinin,
akpm, linux-mm, kernel test robot
On Tue, May 19, 2020 at 08:24:59PM +0200, 'Marco Elver' via kasan-dev wrote:
> 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>
> ---
> mm/kasan/Makefile | 16 ++++++++--------
> mm/kasan/generic.c | 1 -
> 2 files changed, 8 insertions(+), 9 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)
mm/kasan/tags.c:15:9: warning: 'DISABLE_BRANCH_PROFILING' macro redefined [-Wmacro-redefined]
#define DISABLE_BRANCH_PROFILING
^
<command line>:6:9: note: previous definition is here
#define DISABLE_BRANCH_PROFILING 1
^
This?
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>
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] kasan: Disable branch tracing for core runtime
2020-05-21 22:11 ` Qian Cai
@ 2020-05-22 7:54 ` Marco Elver
0 siblings, 0 replies; 5+ messages in thread
From: Marco Elver @ 2020-05-22 7:54 UTC (permalink / raw)
To: Qian Cai
Cc: Dmitry Vyukov, Alexander Potapenko, Andrey Konovalov, LKML,
kasan-dev, Andrey Ryabinin, Andrew Morton,
Linux Memory Management List, kernel test robot
On Fri, 22 May 2020 at 00:11, Qian Cai <cai@lca.pw> wrote:
>
> On Tue, May 19, 2020 at 08:24:59PM +0200, 'Marco Elver' via kasan-dev wrote:
> > 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>
> > ---
> > mm/kasan/Makefile | 16 ++++++++--------
> > mm/kasan/generic.c | 1 -
> > 2 files changed, 8 insertions(+), 9 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)
>
> mm/kasan/tags.c:15:9: warning: 'DISABLE_BRANCH_PROFILING' macro redefined [-Wmacro-redefined]
> #define DISABLE_BRANCH_PROFILING
> ^
> <command line>:6:9: note: previous definition is here
> #define DISABLE_BRANCH_PROFILING 1
> ^
>
> This?
>
> 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>
>
I missed this one, thanks! Added this to v2.
v2: https://lkml.kernel.org/r/20200522075207.157349-1-elver@google.com
^ permalink raw reply [flat|nested] 5+ messages in thread
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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2020-05-19 18:24 [PATCH] kasan: Disable branch tracing for core runtime Marco Elver
2020-05-19 21:05 ` Andrey Konovalov
2020-05-20 0:09 ` Andrew Morton
2020-05-21 22:11 ` Qian Cai
2020-05-22 7:54 ` Marco Elver
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