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

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Anders Roxell

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Dec 12, 2018, 1:36:46 PM12/12/18
to arya...@virtuozzo.com, dvy...@google.com, kasa...@googlegroups.com, linu...@kvack.org, linux-...@vger.kernel.org, ros...@goodmis.org, Anders Roxell
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 <anders...@linaro.org>
---
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

Dmitry Vyukov

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Dec 13, 2018, 3:52:48 AM12/13/18
to anders...@linaro.org, Andrey Ryabinin, kasan-dev, Linux-MM, LKML, Steven Rostedt
On Wed, Dec 12, 2018 at 7:36 PM Anders Roxell <anders...@linaro.org> 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 <dvy...@google.com>

Thanks!
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