diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index 337ae547d008..4efac73a714c 100644
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -573,8 +573,7 @@ static char *cat_backtrace(struct perf_sample *sample,
 }
 
 typedef int (*tracepoint_handler)(struct timechart *tchart,
-				  struct perf_sample *sample,
-				  const char *backtrace);
+				  struct perf_sample *sample);
 
 static int process_sample_event(const struct perf_tool *tool,
 				union perf_event *event __maybe_unused,
@@ -595,7 +594,7 @@ static int process_sample_event(const struct perf_tool *tool,
 	if (evsel->handler != NULL) {
 		tracepoint_handler f = evsel->handler;
 
-		ret = f(tchart, sample, NULL);
+		ret = f(tchart, sample);
 	}
 
 	return ret;
@@ -603,8 +602,7 @@ static int process_sample_event(const struct perf_tool *tool,
 
 static int
 process_sample_cpu_idle(struct timechart *tchart __maybe_unused,
-			struct perf_sample *sample,
-			const char *backtrace __maybe_unused)
+			struct perf_sample *sample)
 {
 	u32 state  = perf_sample__intval(sample, "state");
 	u32 cpu_id = perf_sample__intval(sample, "cpu_id");
@@ -624,8 +622,7 @@ process_sample_cpu_idle(struct timechart *tchart __maybe_unused,
 
 static int
 process_sample_cpu_frequency(struct timechart *tchart,
-			     struct perf_sample *sample,
-			     const char *backtrace __maybe_unused)
+			     struct perf_sample *sample)
 {
 	u32 state  = perf_sample__intval(sample, "state");
 	u32 cpu_id = perf_sample__intval(sample, "cpu_id");
@@ -642,12 +639,12 @@ process_sample_cpu_frequency(struct timechart *tchart,
 
 static int
 process_sample_sched_wakeup(struct timechart *tchart,
-			    struct perf_sample *sample,
-			    const char *backtrace)
+			    struct perf_sample *sample)
 {
 	u8 flags  = perf_sample__intval(sample, "common_flags");
 	int waker = perf_sample__intval(sample, "common_pid");
 	int wakee = perf_sample__intval(sample, "pid");
+	char *backtrace;
 
 	/* perf.data is untrusted input — CPU may be absent or corrupted */
 	if (sample->cpu >= MAX_CPUS) {
@@ -664,12 +661,12 @@ process_sample_sched_wakeup(struct timechart *tchart,
 
 static int
 process_sample_sched_switch(struct timechart *tchart,
-			    struct perf_sample *sample,
-			    const char *backtrace)
+			    struct perf_sample *sample)
 {
 	int prev_pid   = perf_sample__intval(sample, "prev_pid");
 	int next_pid   = perf_sample__intval(sample, "next_pid");
 	u64 prev_state = perf_sample__intval(sample, "prev_state");
+	char *backtrace;
 
 	/* perf.data is untrusted input — CPU may be absent or corrupted */
 	if (sample->cpu >= MAX_CPUS) {
@@ -688,8 +685,7 @@ process_sample_sched_switch(struct timechart *tchart,
 #ifdef SUPPORT_OLD_POWER_EVENTS
 static int
 process_sample_power_start(struct timechart *tchart __maybe_unused,
-			   struct perf_sample *sample,
-			   const char *backtrace __maybe_unused)
+			   struct perf_sample *sample)
 {
 	u64 cpu_id = perf_sample__intval(sample, "cpu_id");
 	u64 value  = perf_sample__intval(sample, "value");
@@ -706,8 +702,7 @@ process_sample_power_start(struct timechart *tchart __maybe_unused,
 
 static int
 process_sample_power_end(struct timechart *tchart,
-			 struct perf_sample *sample,
-			 const char *backtrace __maybe_unused)
+			 struct perf_sample *sample)
 {
 	/* perf.data is untrusted input — CPU may be absent or corrupted */
 	if (sample->cpu >= MAX_CPUS) {
@@ -721,8 +716,7 @@ process_sample_power_end(struct timechart *tchart,
 
 static int
 process_sample_power_frequency(struct timechart *tchart,
-			       struct perf_sample *sample,
-			       const char *backtrace __maybe_unused)
+			       struct perf_sample *sample)
 {
 	u64 cpu_id = perf_sample__intval(sample, "cpu_id");
 	u64 value  = perf_sample__intval(sample, "value");
@@ -895,8 +889,7 @@ static int pid_end_io_sample(struct timechart *tchart, int pid, int type,
 
 static int
 process_enter_read(struct timechart *tchart,
-		   struct perf_sample *sample,
-		   const char *backtrace __maybe_unused)
+		   struct perf_sample *sample)
 {
 	long fd = perf_sample__intval(sample, "fd");
 	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_READ,
@@ -905,8 +898,7 @@ process_enter_read(struct timechart *tchart,
 
 static int
 process_exit_read(struct timechart *tchart,
-		  struct perf_sample *sample,
-		  const char *backtrace __maybe_unused)
+		  struct perf_sample *sample)
 {
 	long ret = perf_sample__intval(sample, "ret");
 	return pid_end_io_sample(tchart, sample->tid, IOTYPE_READ,
@@ -915,8 +907,7 @@ process_exit_read(struct timechart *tchart,
 
 static int
 process_enter_write(struct timechart *tchart,
-		    struct perf_sample *sample,
-		    const char *backtrace __maybe_unused)
+		    struct perf_sample *sample)
 {
 	long fd = perf_sample__intval(sample, "fd");
 	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_WRITE,
@@ -925,8 +916,7 @@ process_enter_write(struct timechart *tchart,
 
 static int
 process_exit_write(struct timechart *tchart,
-		   struct perf_sample *sample,
-		   const char *backtrace __maybe_unused)
+		   struct perf_sample *sample)
 {
 	long ret = perf_sample__intval(sample, "ret");
 	return pid_end_io_sample(tchart, sample->tid, IOTYPE_WRITE,
@@ -935,8 +925,7 @@ process_exit_write(struct timechart *tchart,
 
 static int
 process_enter_sync(struct timechart *tchart,
-		   struct perf_sample *sample,
-		   const char *backtrace __maybe_unused)
+		   struct perf_sample *sample)
 {
 	long fd = perf_sample__intval(sample, "fd");
 	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_SYNC,
@@ -945,8 +934,7 @@ process_enter_sync(struct timechart *tchart,
 
 static int
 process_exit_sync(struct timechart *tchart,
-		  struct perf_sample *sample,
-		  const char *backtrace __maybe_unused)
+		  struct perf_sample *sample)
 {
 	long ret = perf_sample__intval(sample, "ret");
 	return pid_end_io_sample(tchart, sample->tid, IOTYPE_SYNC,
@@ -955,8 +943,7 @@ process_exit_sync(struct timechart *tchart,
 
 static int
 process_enter_tx(struct timechart *tchart,
-		 struct perf_sample *sample,
-		 const char *backtrace __maybe_unused)
+		 struct perf_sample *sample)
 {
 	long fd = perf_sample__intval(sample, "fd");
 	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_TX,
@@ -965,8 +952,7 @@ process_enter_tx(struct timechart *tchart,
 
 static int
 process_exit_tx(struct timechart *tchart,
-		struct perf_sample *sample,
-		const char *backtrace __maybe_unused)
+		struct perf_sample *sample)
 {
 	long ret = perf_sample__intval(sample, "ret");
 	return pid_end_io_sample(tchart, sample->tid, IOTYPE_TX,
@@ -975,8 +961,7 @@ process_exit_tx(struct timechart *tchart,
 
 static int
 process_enter_rx(struct timechart *tchart,
-		 struct perf_sample *sample,
-		 const char *backtrace __maybe_unused)
+		 struct perf_sample *sample)
 {
 	long fd = perf_sample__intval(sample, "fd");
 	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_RX,
@@ -985,8 +970,7 @@ process_enter_rx(struct timechart *tchart,
 
 static int
 process_exit_rx(struct timechart *tchart,
-		struct perf_sample *sample,
-		const char *backtrace __maybe_unused)
+		struct perf_sample *sample)
 {
 	long ret = perf_sample__intval(sample, "ret");
 	return pid_end_io_sample(tchart, sample->tid, IOTYPE_RX,
@@ -995,8 +979,7 @@ process_exit_rx(struct timechart *tchart,
 
 static int
 process_enter_poll(struct timechart *tchart,
-		   struct perf_sample *sample,
-		   const char *backtrace __maybe_unused)
+		   struct perf_sample *sample)
 {
 	long fd = perf_sample__intval(sample, "fd");
 	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_POLL,
@@ -1005,8 +988,7 @@ process_enter_poll(struct timechart *tchart,
 
 static int
 process_exit_poll(struct timechart *tchart,
-		  struct perf_sample *sample,
-		  const char *backtrace __maybe_unused)
+		  struct perf_sample *sample)
 {
 	long ret = perf_sample__intval(sample, "ret");
 	return pid_end_io_sample(tchart, sample->tid, IOTYPE_POLL,