[PATCH 0/3] perf: Disable user space dumps for function trace event

[PATCH 0/3] perf: Disable user space dumps for function trace event

[Jiri Olsa]

hi,
recent issues with user space callchains processing within
page fault handler tracing showed as Peter said 'there's
just too much fail surface'.

Related list discussions:
  http://marc.info/?t=139302086500001&r=1&w=2
  http://marc.info/?t=139301437300003&r=1&w=2

Disabling user space callchain and stack dump for
function trace event. Plus updating the perf tool
to keep up with those changes.

Reachable here:

thanks,
jirka


Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
Jiri Olsa (3):
      perf: Disallow user space callchains for function trace event
      perf: Disallow user space stack dump for function trace event
      perf tools: Disable user space callchain/stack for function trace event

 kernel/trace/trace_event_perf.c | 22 +++++++++++++++++++---
 tools/perf/util/evsel.c         | 41 ++++++++++++++++++++++++++++++-----------
 tools/perf/util/evsel.h         | 18 ++++++++++++++++++
 3 files changed, 67 insertions(+), 14 deletions(-)

[PATCH 1/3] perf: Disallow user space callchains for function trace event

[Jiri Olsa]

Disabling user callchains for function trace event.

Recent issues with user space callchains processing within
page fault handler tracing showed as Peter said 'there's
just too much fail surface'.

Related list discussions:
  http://marc.info/?t=139302086500001&r=1&w=2
  http://marc.info/?t=139301437300003&r=1&w=2

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_event_perf.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index e854f42..d5e01c3 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -31,9 +31,18 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
 	}
 
 	/* The ftrace function trace is allowed only for root. */
-	if (ftrace_event_is_function(tp_event) &&
-	    perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
-		return -EPERM;
+	if (ftrace_event_is_function(tp_event)) {
+		if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		/*
+		 * We don't allow user space callchains for  function trace
+		 * event, due to issues with page faults while tracing page
+		 * fault handler and its overall trickiness nature.
+		 */
+		if (!p_event->attr.exclude_callchain_user)
+			return -EINVAL;
+	}
 
 	/* No tracing, just counting, so no obvious leak */
 	if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW))
-- 
1.8.3.1

[tip:perf/core] perf: Disallow user-space callchains for function trace events

[tip-bot for Jiri Olsa]

Commit-ID:  cfa77bc4af2c75c0781ee76cde2dd104c6c8e2b7
Gitweb:     http://git.kernel.org/tip/cfa77bc4af2c75c0781ee76cde2dd104c6c8e2b7
Author:     Jiri Olsa <jolsa@redhat.com>
AuthorDate: Sun, 2 Mar 2014 16:56:38 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 11 Mar 2014 11:57:57 +0100

perf: Disallow user-space callchains for function trace events

Recent issues with user space callchains processing within
page fault handler tracing showed as Peter said 'there's
just too much fail surface'.

Related list discussions:

  http://marc.info/?t=139302086500001&r=1&w=2
  http://marc.info/?t=139301437300003&r=1&w=2

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1393775800-13524-2-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/trace/trace_event_perf.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index e854f42..d5e01c3 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -31,9 +31,18 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
 	}
 
 	/* The ftrace function trace is allowed only for root. */
-	if (ftrace_event_is_function(tp_event) &&
-	    perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
-		return -EPERM;
+	if (ftrace_event_is_function(tp_event)) {
+		if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		/*
+		 * We don't allow user space callchains for  function trace
+		 * event, due to issues with page faults while tracing page
+		 * fault handler and its overall trickiness nature.
+		 */
+		if (!p_event->attr.exclude_callchain_user)
+			return -EINVAL;
+	}
 
 	/* No tracing, just counting, so no obvious leak */
 	if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW))

[PATCH 2/3] perf: Disallow user space stack dump for function trace event

[Jiri Olsa]

Disabling user space stack dump for function trace event.

Recent issues with user space callchains processing within
page fault handler tracing showed as Peter said 'there's
just too much fail surface'.

The user space stack dump is just another source of the this issue.

Related list discussions:
  http://marc.info/?t=139302086500001&r=1&w=2
  http://marc.info/?t=139301437300003&r=1&w=2

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_event_perf.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index d5e01c3..c894614 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -42,6 +42,13 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
 		 */
 		if (!p_event->attr.exclude_callchain_user)
 			return -EINVAL;
+
+		/*
+		 * Same reason to disable user stack dump as for user space
+		 * callchains above.
+		 */
+		if (p_event->attr.sample_type & PERF_SAMPLE_STACK_USER)
+			return -EINVAL;
 	}
 
 	/* No tracing, just counting, so no obvious leak */
-- 
1.8.3.1

Re: [PATCH 2/3] perf: Disallow user space stack dump for function trace event

[Steven Rostedt]

On Sun,  2 Mar 2014 16:56:39 +0100
Jiri Olsa <jolsa@redhat.com> wrote:

> Disabling user space stack dump for function trace event.
> 
> Recent issues with user space callchains processing within
> page fault handler tracing showed as Peter said 'there's
> just too much fail surface'.
> 
> The user space stack dump is just another source of the this issue.
> 
> Related list discussions:
>   http://marc.info/?t=139302086500001&r=1&w=2
>   http://marc.info/?t=139301437300003&r=1&w=2

For Linux git change logs, it's more preferable to use the kernel.org
link (it may go to the same place, but at least kernel.org has more
control of where it goes in the future).

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1402211521040.6395@vincent-weaver-1.um.maine.edu

-- Steve

> 
> Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Vince Weaver <vincent.weaver@maine.edu>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> ---
>  kernel/trace/trace_event_perf.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
> index d5e01c3..c894614 100644
> --- a/kernel/trace/trace_event_perf.c
> +++ b/kernel/trace/trace_event_perf.c
> @@ -42,6 +42,13 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
>  		 */
>  		if (!p_event->attr.exclude_callchain_user)
>  			return -EINVAL;
> +
> +		/*
> +		 * Same reason to disable user stack dump as for user space
> +		 * callchains above.
> +		 */
> +		if (p_event->attr.sample_type & PERF_SAMPLE_STACK_USER)
> +			return -EINVAL;
>  	}
>  
>  	/* No tracing, just counting, so no obvious leak */

[tip:perf/core] perf: Disallow user-space stack dumps for function trace events

[tip-bot for Jiri Olsa]

Commit-ID:  63c45f4ba533e9749da16298db53e491c25d805b
Gitweb:     http://git.kernel.org/tip/63c45f4ba533e9749da16298db53e491c25d805b
Author:     Jiri Olsa <jolsa@redhat.com>
AuthorDate: Sun, 2 Mar 2014 16:56:39 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 11 Mar 2014 11:57:58 +0100

perf: Disallow user-space stack dumps for function trace events

Recent issues with user space callchains processing within
page fault handler tracing showed as Peter said 'there's
just too much fail surface'.

The user space stack dump is just another source of the this issue.

Related list discussions:
  http://marc.info/?t=139302086500001&r=1&w=2
  http://marc.info/?t=139301437300003&r=1&w=2

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1393775800-13524-3-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/trace/trace_event_perf.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index d5e01c3..c894614 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -42,6 +42,13 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
 		 */
 		if (!p_event->attr.exclude_callchain_user)
 			return -EINVAL;
+
+		/*
+		 * Same reason to disable user stack dump as for user space
+		 * callchains above.
+		 */
+		if (p_event->attr.sample_type & PERF_SAMPLE_STACK_USER)
+			return -EINVAL;
 	}
 
 	/* No tracing, just counting, so no obvious leak */

[PATCH 3/3] perf tools: Disable user space callchain/stack for function trace event

[Jiri Olsa]

User space callchains and user space stack dump were disabled
for function trace event. Mailing list discussions:
  http://marc.info/?t=139302086500001&r=1&w=2
  http://marc.info/?t=139301437300003&r=1&w=2

Catching up with perf and disabling user space callchains and
DWARF unwind (uses user stack dump) for function trace event.

Adding following warnings when callchains are used
for function trace event:

  # perf record -g -e ftrace:function ...
  Disabling user space callchains for function trace event.
  ...

  # ./perf record --call-graph=dwarf -e ftrace:function ...
  Cannot use DWARF unwind for function trace event, falling back to framepointers.
  Disabling user space callchains for function trace event.
  ...

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
 tools/perf/util/evsel.c | 41 ++++++++++++++++++++++++++++++-----------
 tools/perf/util/evsel.h | 18 ++++++++++++++++++
 2 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index adc94dd..26b67b1 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -500,6 +500,34 @@ int perf_evsel__group_desc(struct perf_evsel *evsel, char *buf, size_t size)
 	return ret;
 }
 
+static void
+perf_evsel__config_callgraph(struct perf_evsel *evsel,
+			     struct record_opts *opts)
+{
+	bool function = perf_evsel__is_function_event(evsel);
+	struct perf_event_attr *attr = &evsel->attr;
+
+	perf_evsel__set_sample_bit(evsel, CALLCHAIN);
+
+	if (opts->call_graph == CALLCHAIN_DWARF) {
+		if (!function) {
+			perf_evsel__set_sample_bit(evsel, REGS_USER);
+			perf_evsel__set_sample_bit(evsel, STACK_USER);
+			attr->sample_regs_user = PERF_REGS_MASK;
+			attr->sample_stack_user = opts->stack_dump_size;
+			attr->exclude_callchain_user = 1;
+		} else {
+			pr_info("Cannot use DWARF unwind for function trace event,"
+				" falling back to framepointers.\n");
+		}
+	}
+
+	if (function) {
+		pr_info("Disabling user space callchains for function trace event.\n");
+		attr->exclude_callchain_user = 1;
+	}
+}
+
 /*
  * The enable_on_exec/disabled value strategy:
  *
@@ -595,17 +623,8 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
 		attr->mmap_data = track;
 	}
 
-	if (opts->call_graph_enabled) {
-		perf_evsel__set_sample_bit(evsel, CALLCHAIN);
-
-		if (opts->call_graph == CALLCHAIN_DWARF) {
-			perf_evsel__set_sample_bit(evsel, REGS_USER);
-			perf_evsel__set_sample_bit(evsel, STACK_USER);
-			attr->sample_regs_user = PERF_REGS_MASK;
-			attr->sample_stack_user = opts->stack_dump_size;
-			attr->exclude_callchain_user = 1;
-		}
-	}
+	if (opts->call_graph_enabled)
+		perf_evsel__config_callgraph(evsel, opts);
 
 	if (target__has_cpu(&opts->target))
 		perf_evsel__set_sample_bit(evsel, CPU);
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index f1b3256..0c9926c 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -315,6 +315,24 @@ static inline bool perf_evsel__is_group_event(struct perf_evsel *evsel)
 	return perf_evsel__is_group_leader(evsel) && evsel->nr_members > 1;
 }
 
+/**
+ * perf_evsel__is_function_event - Return whether given evsel is a function
+ * trace event
+ *
+ * @evsel - evsel selector to be tested
+ *
+ * Return %true if event is function trace event
+ */
+static inline bool perf_evsel__is_function_event(struct perf_evsel *evsel)
+{
+#define FUNCTION_EVENT "ftrace:function"
+
+	return evsel->name &&
+	       !strncmp(FUNCTION_EVENT, evsel->name, sizeof(FUNCTION_EVENT));
+
+#undef FUNCTION_EVENT
+}
+
 struct perf_attr_details {
 	bool freq;
 	bool verbose;
-- 
1.8.3.1

[tip:perf/core] perf tools: Disable user-space callchain/ stack dumps for function trace events

[tip-bot for Jiri Olsa]

Commit-ID:  6bedfab68666afac1b03f8d62ee037c6ab82fbc5
Gitweb:     http://git.kernel.org/tip/6bedfab68666afac1b03f8d62ee037c6ab82fbc5
Author:     Jiri Olsa <jolsa@redhat.com>
AuthorDate: Sun, 2 Mar 2014 16:56:40 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 11 Mar 2014 11:57:59 +0100

perf tools: Disable user-space callchain/stack dumps for function trace events

User space callchains and user space stack dump were disabled
for function trace event. Mailing list discussions:

  http://marc.info/?t=139302086500001&r=1&w=2
  http://marc.info/?t=139301437300003&r=1&w=2

Catching up with perf and disabling user space callchains and
DWARF unwind (uses user stack dump) for function trace event.

Adding following warnings when callchains are used
for function trace event:

  # perf record -g -e ftrace:function ...
  Disabling user space callchains for function trace event.
  ...

  # ./perf record --call-graph=dwarf -e ftrace:function ...
  Cannot use DWARF unwind for function trace event, falling back to framepointers.
  Disabling user space callchains for function trace event.
  ...

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1393775800-13524-4-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 tools/perf/util/evsel.c | 41 ++++++++++++++++++++++++++++++-----------
 tools/perf/util/evsel.h | 18 ++++++++++++++++++
 2 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index adc94dd..26b67b1 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -500,6 +500,34 @@ int perf_evsel__group_desc(struct perf_evsel *evsel, char *buf, size_t size)
 	return ret;
 }
 
+static void
+perf_evsel__config_callgraph(struct perf_evsel *evsel,
+			     struct record_opts *opts)
+{
+	bool function = perf_evsel__is_function_event(evsel);
+	struct perf_event_attr *attr = &evsel->attr;
+
+	perf_evsel__set_sample_bit(evsel, CALLCHAIN);
+
+	if (opts->call_graph == CALLCHAIN_DWARF) {
+		if (!function) {
+			perf_evsel__set_sample_bit(evsel, REGS_USER);
+			perf_evsel__set_sample_bit(evsel, STACK_USER);
+			attr->sample_regs_user = PERF_REGS_MASK;
+			attr->sample_stack_user = opts->stack_dump_size;
+			attr->exclude_callchain_user = 1;
+		} else {
+			pr_info("Cannot use DWARF unwind for function trace event,"
+				" falling back to framepointers.\n");
+		}
+	}
+
+	if (function) {
+		pr_info("Disabling user space callchains for function trace event.\n");
+		attr->exclude_callchain_user = 1;
+	}
+}
+
 /*
  * The enable_on_exec/disabled value strategy:
  *
@@ -595,17 +623,8 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
 		attr->mmap_data = track;
 	}
 
-	if (opts->call_graph_enabled) {
-		perf_evsel__set_sample_bit(evsel, CALLCHAIN);
-
-		if (opts->call_graph == CALLCHAIN_DWARF) {
-			perf_evsel__set_sample_bit(evsel, REGS_USER);
-			perf_evsel__set_sample_bit(evsel, STACK_USER);
-			attr->sample_regs_user = PERF_REGS_MASK;
-			attr->sample_stack_user = opts->stack_dump_size;
-			attr->exclude_callchain_user = 1;
-		}
-	}
+	if (opts->call_graph_enabled)
+		perf_evsel__config_callgraph(evsel, opts);
 
 	if (target__has_cpu(&opts->target))
 		perf_evsel__set_sample_bit(evsel, CPU);
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index f1b3256..0c9926c 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -315,6 +315,24 @@ static inline bool perf_evsel__is_group_event(struct perf_evsel *evsel)
 	return perf_evsel__is_group_leader(evsel) && evsel->nr_members > 1;
 }
 
+/**
+ * perf_evsel__is_function_event - Return whether given evsel is a function
+ * trace event
+ *
+ * @evsel - evsel selector to be tested
+ *
+ * Return %true if event is function trace event
+ */
+static inline bool perf_evsel__is_function_event(struct perf_evsel *evsel)
+{
+#define FUNCTION_EVENT "ftrace:function"
+
+	return evsel->name &&
+	       !strncmp(FUNCTION_EVENT, evsel->name, sizeof(FUNCTION_EVENT));
+
+#undef FUNCTION_EVENT
+}
+
 struct perf_attr_details {
 	bool freq;
 	bool verbose;

Re: [PATCH 0/3] perf: Disable user space dumps for function trace event

[Jiri Olsa]

On Sun, Mar 02, 2014 at 04:56:37PM +0100, Jiri Olsa wrote:
> hi,
> recent issues with user space callchains processing within
> page fault handler tracing showed as Peter said 'there's
> just too much fail surface'.
> 
> Related list discussions:
>   http://marc.info/?t=139302086500001&r=1&w=2
>   http://marc.info/?t=139301437300003&r=1&w=2
> 
> Disabling user space callchain and stack dump for
> function trace event. Plus updating the perf tool
> to keep up with those changes.
> 

Reachable here:
  git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
  perf/function_trace_fixies_1

jirka