2018-12-12 18:39:45

by Anders Roxell

Subject: [PATCH v2] kasan: mark file common so ftrace doesn't trace it

When option CONFIG_KASAN is enabled toghether with ftrace, function
ftrace_graph_caller() gets in to a recursion, via functions
kasan_check_read() and kasan_check_write().

Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
179 mcount_get_pc x0 // function's pc
(gdb) bt
#0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
#1 0xffffff90101406c8 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151
#2 0xffffff90106fd084 in kasan_check_write (p=0xffffffc06c170878, size=4) at ../mm/kasan/common.c:105
#3 0xffffff90104a2464 in atomic_add_return (v=<optimized out>, i=<optimized out>) at ./include/generated/atomic-instrumented.h:71
#4 atomic_inc_return (v=<optimized out>) at ./include/generated/atomic-fallback.h:284
#5 trace_graph_entry (trace=0xffffffc03f5ff380) at ../kernel/trace/trace_functions_graph.c:441
#6 0xffffff9010481774 in trace_graph_entry_watchdog (trace=<optimized out>) at ../kernel/trace/trace_selftest.c:741
#7 0xffffff90104a185c in function_graph_enter (ret=<optimized out>, func=<optimized out>, frame_pointer=18446743799894897728, retp=<optimized out>) at ../kernel/trace/trace_functions_graph.c:196
#8 0xffffff9010140628 in prepare_ftrace_return (self_addr=18446743592948977792, parent=0xffffffc03f5ff418, frame_pointer=18446743799894897728) at ../arch/arm64/kernel/ftrace.c:231
#9 0xffffff90101406f4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb)

Rework so that the kasan implementation isn't traced.

Signed-off-by: Anders Roxell <[email protected]>
---
mm/kasan/Makefile | 1 +
1 file changed, 1 insertion(+)

diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index 0a14fcff70ed..e2bb06c1b45e 100644
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -5,6 +5,7 @@ UBSAN_SANITIZE_generic.o := n
UBSAN_SANITIZE_tags.o := n
KCOV_INSTRUMENT := n

+CFLAGS_REMOVE_common.o = -pg
CFLAGS_REMOVE_generic.o = -pg
# Function splitter causes unnecessary splits in __asan_load1/__asan_store1
# see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533
--
2.19.2

2018-12-13 08:55:13

by Dmitry Vyukov

Subject: Re: [PATCH v2] kasan: mark file common so ftrace doesn't trace it

On Wed, Dec 12, 2018 at 7:36 PM Anders Roxell <[email protected]> wrote:
>
> When option CONFIG_KASAN is enabled toghether with ftrace, function
> ftrace_graph_caller() gets in to a recursion, via functions
> kasan_check_read() and kasan_check_write().
>
> Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
> 179 mcount_get_pc x0 // function's pc
> (gdb) bt
> #0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
> #1 0xffffff90101406c8 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151
> #2 0xffffff90106fd084 in kasan_check_write (p=0xffffffc06c170878, size=4) at ../mm/kasan/common.c:105
> #3 0xffffff90104a2464 in atomic_add_return (v=<optimized out>, i=<optimized out>) at ./include/generated/atomic-instrumented.h:71
> #4 atomic_inc_return (v=<optimized out>) at ./include/generated/atomic-fallback.h:284
> #5 trace_graph_entry (trace=0xffffffc03f5ff380) at ../kernel/trace/trace_functions_graph.c:441
> #6 0xffffff9010481774 in trace_graph_entry_watchdog (trace=<optimized out>) at ../kernel/trace/trace_selftest.c:741
> #7 0xffffff90104a185c in function_graph_enter (ret=<optimized out>, func=<optimized out>, frame_pointer=18446743799894897728, retp=<optimized out>) at ../kernel/trace/trace_functions_graph.c:196
> #8 0xffffff9010140628 in prepare_ftrace_return (self_addr=18446743592948977792, parent=0xffffffc03f5ff418, frame_pointer=18446743799894897728) at ../arch/arm64/kernel/ftrace.c:231
> #9 0xffffff90101406f4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182
> Backtrace stopped: previous frame identical to this frame (corrupt stack?)
> (gdb)
>
> Rework so that the kasan implementation isn't traced.

Acked-by: Dmitry Vyukov <[email protected]>

Thanks!

> Signed-off-by: Anders Roxell <[email protected]>
> ---
> mm/kasan/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
> index 0a14fcff70ed..e2bb06c1b45e 100644
> --- a/mm/kasan/Makefile
> +++ b/mm/kasan/Makefile
> @@ -5,6 +5,7 @@ UBSAN_SANITIZE_generic.o := n
> UBSAN_SANITIZE_tags.o := n
> KCOV_INSTRUMENT := n
>
> +CFLAGS_REMOVE_common.o = -pg
> CFLAGS_REMOVE_generic.o = -pg
> # Function splitter causes unnecessary splits in __asan_load1/__asan_store1
> # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533
> --
> 2.19.2
>