subject:"\[PATCH v4 3\/6\] arm64\: ftrace\: fix a stack tracer's output under function graph tracer"

Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

2015-11-03 Thread AKASHI Takahiro


On 11/01/2015 05:00 PM, Jungseok Lee wrote:

On Oct 30, 2015, at 2:25 PM, AKASHI Takahiro wrote:

Hi Akashi,


Function graph tracer modifies a return address (LR) in a stack frame
to hook a function return. This will result in many useless entries
(return_to_handler) showing up in a stack tracer's output.

This patch replaces such entries with originals values preserved in
current->ret_stack[].

Signed-off-by: AKASHI Takahiro 
---
arch/arm64/include/asm/ftrace.h |2 ++
arch/arm64/kernel/stacktrace.c  |   21 +
2 files changed, 23 insertions(+)

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 2b43e20..b7d597c 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -29,6 +29,8 @@ struct dyn_arch_ftrace {

extern unsigned long ftrace_graph_call;

+extern void return_to_handler(void);
+
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
/*
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index bc0689a..631c49d 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -17,6 +17,7 @@
  */
#include 
#include 
+#include 
#include 
#include 

@@ -78,6 +79,9 @@ struct stack_trace_data {
struct stack_trace *trace;
unsigned int no_sched_functions;
unsigned int skip;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   unsigned int ret_stack_index;
+#endif
};

static int save_trace(struct stackframe *frame, void *d)
@@ -86,6 +90,20 @@ static int save_trace(struct stackframe *frame, void *d)
struct stack_trace *trace = data->trace;
unsigned long addr = frame->pc;

+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   if (addr == (unsigned long)return_to_handler - AARCH64_INSN_SIZE) {
+   /*
+* This is a case where function graph tracer has
+* modified a return address (LR) in a stack frame
+* to hook a function return.
+* So replace it to an original value.
+*/
+   frame->pc = addr =
+   current->ret_stack[data->ret_stack_index--].ret
+   - AARCH64_INSN_SIZE;
+   }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+


This hunk would be affected as the commit, "ARM64: unwind: Fix PC calculation",
e306dfd0, has been reverted.


Yeah, we don't need apply this patch any more.
The other patches in the series will not be affected.

Thanks,
-Takahiro AKASHI



Best Regards
Jungseok Lee


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Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

2015-11-03 Thread AKASHI Takahiro


On 11/01/2015 05:00 PM, Jungseok Lee wrote:

On Oct 30, 2015, at 2:25 PM, AKASHI Takahiro wrote:

Hi Akashi,


Function graph tracer modifies a return address (LR) in a stack frame
to hook a function return. This will result in many useless entries
(return_to_handler) showing up in a stack tracer's output.

This patch replaces such entries with originals values preserved in
current->ret_stack[].

Signed-off-by: AKASHI Takahiro 
---
arch/arm64/include/asm/ftrace.h |2 ++
arch/arm64/kernel/stacktrace.c  |   21 +
2 files changed, 23 insertions(+)

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 2b43e20..b7d597c 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -29,6 +29,8 @@ struct dyn_arch_ftrace {

extern unsigned long ftrace_graph_call;

+extern void return_to_handler(void);
+
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
/*
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index bc0689a..631c49d 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -17,6 +17,7 @@
  */
#include 
#include 
+#include 
#include 
#include 

@@ -78,6 +79,9 @@ struct stack_trace_data {
struct stack_trace *trace;
unsigned int no_sched_functions;
unsigned int skip;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   unsigned int ret_stack_index;
+#endif
};

static int save_trace(struct stackframe *frame, void *d)
@@ -86,6 +90,20 @@ static int save_trace(struct stackframe *frame, void *d)
struct stack_trace *trace = data->trace;
unsigned long addr = frame->pc;

+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   if (addr == (unsigned long)return_to_handler - AARCH64_INSN_SIZE) {
+   /*
+* This is a case where function graph tracer has
+* modified a return address (LR) in a stack frame
+* to hook a function return.
+* So replace it to an original value.
+*/
+   frame->pc = addr =
+   current->ret_stack[data->ret_stack_index--].ret
+   - AARCH64_INSN_SIZE;
+   }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+


This hunk would be affected as the commit, "ARM64: unwind: Fix PC calculation",
e306dfd0, has been reverted.


Yeah, we don't need apply this patch any more.
The other patches in the series will not be affected.

Thanks,
-Takahiro AKASHI



Best Regards
Jungseok Lee


--
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the body of a message to majord...@vger.kernel.org
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Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

2015-11-01 Thread Jungseok Lee

On Oct 30, 2015, at 2:25 PM, AKASHI Takahiro wrote:

Hi Akashi,

> Function graph tracer modifies a return address (LR) in a stack frame
> to hook a function return. This will result in many useless entries
> (return_to_handler) showing up in a stack tracer's output.
> 
> This patch replaces such entries with originals values preserved in
> current->ret_stack[].
> 
> Signed-off-by: AKASHI Takahiro 
> ---
> arch/arm64/include/asm/ftrace.h |2 ++
> arch/arm64/kernel/stacktrace.c  |   21 +
> 2 files changed, 23 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index 2b43e20..b7d597c 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -29,6 +29,8 @@ struct dyn_arch_ftrace {
> 
> extern unsigned long ftrace_graph_call;
> 
> +extern void return_to_handler(void);
> +
> static inline unsigned long ftrace_call_adjust(unsigned long addr)
> {
>   /*
> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index bc0689a..631c49d 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -17,6 +17,7 @@
>  */
> #include 
> #include 
> +#include 
> #include 
> #include 
> 
> @@ -78,6 +79,9 @@ struct stack_trace_data {
>   struct stack_trace *trace;
>   unsigned int no_sched_functions;
>   unsigned int skip;
> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> + unsigned int ret_stack_index;
> +#endif
> };
> 
> static int save_trace(struct stackframe *frame, void *d)
> @@ -86,6 +90,20 @@ static int save_trace(struct stackframe *frame, void *d)
>   struct stack_trace *trace = data->trace;
>   unsigned long addr = frame->pc;
> 
> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> + if (addr == (unsigned long)return_to_handler - AARCH64_INSN_SIZE) {
> + /*
> +  * This is a case where function graph tracer has
> +  * modified a return address (LR) in a stack frame
> +  * to hook a function return.
> +  * So replace it to an original value.
> +  */
> + frame->pc = addr =
> + current->ret_stack[data->ret_stack_index--].ret
> + - AARCH64_INSN_SIZE;
> + }
> +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
> +

This hunk would be affected as the commit, "ARM64: unwind: Fix PC calculation",
e306dfd0, has been reverted.

Best Regards
Jungseok Lee--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

2015-11-01 Thread Jungseok Lee

On Oct 30, 2015, at 2:25 PM, AKASHI Takahiro wrote:

Hi Akashi,

> Function graph tracer modifies a return address (LR) in a stack frame
> to hook a function return. This will result in many useless entries
> (return_to_handler) showing up in a stack tracer's output.
> 
> This patch replaces such entries with originals values preserved in
> current->ret_stack[].
> 
> Signed-off-by: AKASHI Takahiro 
> ---
> arch/arm64/include/asm/ftrace.h |2 ++
> arch/arm64/kernel/stacktrace.c  |   21 +
> 2 files changed, 23 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index 2b43e20..b7d597c 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -29,6 +29,8 @@ struct dyn_arch_ftrace {
> 
> extern unsigned long ftrace_graph_call;
> 
> +extern void return_to_handler(void);
> +
> static inline unsigned long ftrace_call_adjust(unsigned long addr)
> {
>   /*
> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index bc0689a..631c49d 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -17,6 +17,7 @@
>  */
> #include 
> #include 
> +#include 
> #include 
> #include 
> 
> @@ -78,6 +79,9 @@ struct stack_trace_data {
>   struct stack_trace *trace;
>   unsigned int no_sched_functions;
>   unsigned int skip;
> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> + unsigned int ret_stack_index;
> +#endif
> };
> 
> static int save_trace(struct stackframe *frame, void *d)
> @@ -86,6 +90,20 @@ static int save_trace(struct stackframe *frame, void *d)
>   struct stack_trace *trace = data->trace;
>   unsigned long addr = frame->pc;
> 
> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> + if (addr == (unsigned long)return_to_handler - AARCH64_INSN_SIZE) {
> + /*
> +  * This is a case where function graph tracer has
> +  * modified a return address (LR) in a stack frame
> +  * to hook a function return.
> +  * So replace it to an original value.
> +  */
> + frame->pc = addr =
> + current->ret_stack[data->ret_stack_index--].ret
> + - AARCH64_INSN_SIZE;
> + }
> +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
> +

This hunk would be affected as the commit, "ARM64: unwind: Fix PC calculation",
e306dfd0, has been reverted.

Best Regards
Jungseok Lee--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

2015-10-29 Thread AKASHI Takahiro

Function graph tracer modifies a return address (LR) in a stack frame
to hook a function return. This will result in many useless entries
(return_to_handler) showing up in a stack tracer's output.

This patch replaces such entries with originals values preserved in
current->ret_stack[].

Signed-off-by: AKASHI Takahiro 
---
 arch/arm64/include/asm/ftrace.h |2 ++
 arch/arm64/kernel/stacktrace.c  |   21 +
 2 files changed, 23 insertions(+)

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 2b43e20..b7d597c 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -29,6 +29,8 @@ struct dyn_arch_ftrace {
 
 extern unsigned long ftrace_graph_call;
 
+extern void return_to_handler(void);
+
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
/*
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index bc0689a..631c49d 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -17,6 +17,7 @@
  */
 #include 
 #include 
+#include 
 #include 
 #include 
 
@@ -78,6 +79,9 @@ struct stack_trace_data {
struct stack_trace *trace;
unsigned int no_sched_functions;
unsigned int skip;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   unsigned int ret_stack_index;
+#endif
 };
 
 static int save_trace(struct stackframe *frame, void *d)
@@ -86,6 +90,20 @@ static int save_trace(struct stackframe *frame, void *d)
struct stack_trace *trace = data->trace;
unsigned long addr = frame->pc;
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   if (addr == (unsigned long)return_to_handler - AARCH64_INSN_SIZE) {
+   /*
+* This is a case where function graph tracer has
+* modified a return address (LR) in a stack frame
+* to hook a function return.
+* So replace it to an original value.
+*/
+   frame->pc = addr =
+   current->ret_stack[data->ret_stack_index--].ret
+   - AARCH64_INSN_SIZE;
+   }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
if (data->no_sched_functions && in_sched_functions(addr))
return 0;
if (data->skip) {
@@ -105,6 +123,9 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct 
stack_trace *trace)
 
data.trace = trace;
data.skip = trace->skip;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   data.ret_stack_index = current->curr_ret_stack;
+#endif
 
if (tsk != current) {
data.no_sched_functions = 1;
-- 
1.7.9.5

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[PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

2015-10-29 Thread AKASHI Takahiro

Function graph tracer modifies a return address (LR) in a stack frame
to hook a function return. This will result in many useless entries
(return_to_handler) showing up in a stack tracer's output.

This patch replaces such entries with originals values preserved in
current->ret_stack[].

Signed-off-by: AKASHI Takahiro 
---
 arch/arm64/include/asm/ftrace.h |2 ++
 arch/arm64/kernel/stacktrace.c  |   21 +
 2 files changed, 23 insertions(+)

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 2b43e20..b7d597c 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -29,6 +29,8 @@ struct dyn_arch_ftrace {
 
 extern unsigned long ftrace_graph_call;
 
+extern void return_to_handler(void);
+
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
/*
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index bc0689a..631c49d 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -17,6 +17,7 @@
  */
 #include 
 #include 
+#include 
 #include 
 #include 
 
@@ -78,6 +79,9 @@ struct stack_trace_data {
struct stack_trace *trace;
unsigned int no_sched_functions;
unsigned int skip;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   unsigned int ret_stack_index;
+#endif
 };
 
 static int save_trace(struct stackframe *frame, void *d)
@@ -86,6 +90,20 @@ static int save_trace(struct stackframe *frame, void *d)
struct stack_trace *trace = data->trace;
unsigned long addr = frame->pc;
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   if (addr == (unsigned long)return_to_handler - AARCH64_INSN_SIZE) {
+   /*
+* This is a case where function graph tracer has
+* modified a return address (LR) in a stack frame
+* to hook a function return.
+* So replace it to an original value.
+*/
+   frame->pc = addr =
+   current->ret_stack[data->ret_stack_index--].ret
+   - AARCH64_INSN_SIZE;
+   }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
if (data->no_sched_functions && in_sched_functions(addr))
return 0;
if (data->skip) {
@@ -105,6 +123,9 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct 
stack_trace *trace)
 
data.trace = trace;
data.skip = trace->skip;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+   data.ret_stack_index = current->curr_ret_stack;
+#endif
 
if (tsk != current) {
data.no_sched_functions = 1;
-- 
1.7.9.5

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Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

Re: [PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

[PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

[PATCH v4 3/6] arm64: ftrace: fix a stack tracer's output under function graph tracer

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