1 files changed, 103 insertions, 23 deletions

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5edbf6b1da3f..89877a18f933 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -135,6 +135,7 @@ enum hist_field_fn {
 	HIST_FIELD_FN_DIV_NOT_POWER2,
 	HIST_FIELD_FN_DIV_MULT_SHIFT,
 	HIST_FIELD_FN_EXECNAME,
+	HIST_FIELD_FN_STACK,
 };
 
 /*
@@ -480,10 +481,6 @@ DEFINE_HIST_FIELD_FN(u8);
 #define for_each_hist_key_field(i, hist_data)	\
 	for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
 
-#define HIST_STACKTRACE_DEPTH	16
-#define HIST_STACKTRACE_SIZE	(HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
-#define HIST_STACKTRACE_SKIP	5
-
 #define HITCOUNT_IDX		0
 #define HIST_KEY_SIZE_MAX	(MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
 
@@ -1360,7 +1357,12 @@ static const char *hist_field_name(struct hist_field *field,
 			field_name = field->name;
 	} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
 		field_name = "common_timestamp";
-	else if (field->flags & HIST_FIELD_FL_HITCOUNT)
+	else if (field->flags & HIST_FIELD_FL_STACKTRACE) {
+		if (field->field)
+			field_name = field->field->name;
+		else
+			field_name = "stacktrace";
+	} else if (field->flags & HIST_FIELD_FL_HITCOUNT)
 		field_name = "hitcount";
 
 	if (field_name == NULL)
@@ -1718,6 +1720,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
 		flags_str = "percent";
 	else if (hist_field->flags & HIST_FIELD_FL_GRAPH)
 		flags_str = "graph";
+	else if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
+		flags_str = "stacktrace";
 
 	return flags_str;
 }
@@ -1979,7 +1983,14 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
 	}
 
 	if (flags & HIST_FIELD_FL_STACKTRACE) {
-		hist_field->fn_num = HIST_FIELD_FN_NOP;
+		if (field)
+			hist_field->fn_num = HIST_FIELD_FN_STACK;
+		else
+			hist_field->fn_num = HIST_FIELD_FN_NOP;
+		hist_field->size = HIST_STACKTRACE_SIZE;
+		hist_field->type = kstrdup_const("unsigned long[]", GFP_KERNEL);
+		if (!hist_field->type)
+			goto free;
 		goto out;
 	}
 
@@ -2312,6 +2323,8 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 			*flags |= HIST_FIELD_FL_EXECNAME;
 		else if (strcmp(modifier, "syscall") == 0)
 			*flags |= HIST_FIELD_FL_SYSCALL;
+		else if (strcmp(modifier, "stacktrace") == 0)
+			*flags |= HIST_FIELD_FL_STACKTRACE;
 		else if (strcmp(modifier, "log2") == 0)
 			*flags |= HIST_FIELD_FL_LOG2;
 		else if (strcmp(modifier, "usecs") == 0)
@@ -2351,6 +2364,8 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 		hist_data->enable_timestamps = true;
 		if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
 			hist_data->attrs->ts_in_usecs = true;
+	} else if (strcmp(field_name, "stacktrace") == 0) {
+		*flags |= HIST_FIELD_FL_STACKTRACE;
 	} else if (strcmp(field_name, "common_cpu") == 0)
 		*flags |= HIST_FIELD_FL_CPU;
 	else if (strcmp(field_name, "hitcount") == 0)
@@ -3111,6 +3126,9 @@ static inline void __update_field_vars(struct tracing_map_elt *elt,
 	unsigned int i, j, var_idx;
 	u64 var_val;
 
+	/* Make sure stacktrace can fit in the string variable length */
+	BUILD_BUG_ON((HIST_STACKTRACE_DEPTH + 1) * sizeof(long) >= STR_VAR_LEN_MAX);
+
 	for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
 		struct field_var *field_var = field_vars[i];
 		struct hist_field *var = field_var->var;
@@ -3119,13 +3137,26 @@ static inline void __update_field_vars(struct tracing_map_elt *elt,
 		var_val = hist_fn_call(val, elt, buffer, rbe, rec);
 		var_idx = var->var.idx;
 
-		if (val->flags & HIST_FIELD_FL_STRING) {
+		if (val->flags & (HIST_FIELD_FL_STRING |
+				  HIST_FIELD_FL_STACKTRACE)) {
 			char *str = elt_data->field_var_str[j++];
 			char *val_str = (char *)(uintptr_t)var_val;
 			unsigned int size;
 
-			size = min(val->size, STR_VAR_LEN_MAX);
-			strscpy(str, val_str, size);
+			if (val->flags & HIST_FIELD_FL_STRING) {
+				size = min(val->size, STR_VAR_LEN_MAX);
+				strscpy(str, val_str, size);
+			} else {
+				char *stack_start = str + sizeof(unsigned long);
+				int e;
+
+				e = stack_trace_save((void *)stack_start,
+						     HIST_STACKTRACE_DEPTH,
+						     HIST_STACKTRACE_SKIP);
+				if (e < HIST_STACKTRACE_DEPTH - 1)
+					((unsigned long *)stack_start)[e] = 0;
+				*((unsigned long *)str) = e;
+			}
 			var_val = (u64)(uintptr_t)str;
 		}
 		tracing_map_set_var(elt, var_idx, var_val);
@@ -3824,7 +3855,8 @@ static void save_field_var(struct hist_trigger_data *hist_data,
 {
 	hist_data->field_vars[hist_data->n_field_vars++] = field_var;
 
-	if (field_var->val->flags & HIST_FIELD_FL_STRING)
+	/* Stack traces are saved in the string storage too */
+	if (field_var->val->flags & (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
 		hist_data->n_field_var_str++;
 }
 
@@ -3849,6 +3881,9 @@ static int check_synth_field(struct synth_event *event,
 	    && field->is_dynamic)
 		return 0;
 
+	if (strstr(hist_field->type, "long[") && field->is_stack)
+		return 0;
+
 	if (strcmp(field->type, hist_field->type) != 0) {
 		if (field->size != hist_field->size ||
 		    (!field->is_string && field->is_signed != hist_field->is_signed))
@@ -4103,7 +4138,8 @@ static int action_create(struct hist_trigger_data *hist_data,
 			}
 
 			hist_data->save_vars[hist_data->n_save_vars++] = field_var;
-			if (field_var->val->flags & HIST_FIELD_FL_STRING)
+			if (field_var->val->flags &
+			    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
 				hist_data->n_save_var_str++;
 			kfree(param);
 		}
@@ -4242,6 +4278,19 @@ static u64 hist_field_execname(struct hist_field *hist_field,
 	return (u64)(unsigned long)(elt_data->comm);
 }
 
+static u64 hist_field_stack(struct hist_field *hist_field,
+			    struct tracing_map_elt *elt,
+			    struct trace_buffer *buffer,
+			    struct ring_buffer_event *rbe,
+			    void *event)
+{
+	u32 str_item = *(u32 *)(event + hist_field->field->offset);
+	int str_loc = str_item & 0xffff;
+	char *addr = (char *)(event + str_loc);
+
+	return (u64)(unsigned long)addr;
+}
+
 static u64 hist_fn_call(struct hist_field *hist_field,
 			struct tracing_map_elt *elt,
 			struct trace_buffer *buffer,
@@ -4305,6 +4354,8 @@ static u64 hist_fn_call(struct hist_field *hist_field,
 		return div_by_mult_and_shift(hist_field, elt, buffer, rbe, event);
 	case HIST_FIELD_FN_EXECNAME:
 		return hist_field_execname(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_STACK:
+		return hist_field_stack(hist_field, elt, buffer, rbe, event);
 	default:
 		return 0;
 	}
@@ -4351,7 +4402,8 @@ static int create_var_field(struct hist_trigger_data *hist_data,
 	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
 		update_var_execname(hist_data->fields[val_idx]);
 
-	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
+	if (!ret && hist_data->fields[val_idx]->flags &
+	    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE))
 		hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
 
 	return ret;
@@ -5092,7 +5144,8 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
 		if (hist_field->flags & HIST_FIELD_FL_VAR) {
 			var_idx = hist_field->var.idx;
 
-			if (hist_field->flags & HIST_FIELD_FL_STRING) {
+			if (hist_field->flags &
+			    (HIST_FIELD_FL_STRING | HIST_FIELD_FL_STACKTRACE)) {
 				unsigned int str_start, var_str_idx, idx;
 				char *str, *val_str;
 				unsigned int size;
@@ -5105,9 +5158,20 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
 				str = elt_data->field_var_str[idx];
 				val_str = (char *)(uintptr_t)hist_val;
 
-				size = min(hist_field->size, STR_VAR_LEN_MAX);
-				strscpy(str, val_str, size);
-
+				if (hist_field->flags & HIST_FIELD_FL_STRING) {
+					size = min(hist_field->size, STR_VAR_LEN_MAX);
+					strscpy(str, val_str, size);
+				} else {
+					char *stack_start = str + sizeof(unsigned long);
+					int e;
+
+					e = stack_trace_save((void *)stack_start,
+							     HIST_STACKTRACE_DEPTH,
+							     HIST_STACKTRACE_SKIP);
+					if (e < HIST_STACKTRACE_DEPTH - 1)
+						((unsigned long *)stack_start)[e] = 0;
+					*((unsigned long *)str) = e;
+				}
 				hist_val = (u64)(uintptr_t)str;
 			}
 			tracing_map_set_var(elt, var_idx, hist_val);
@@ -5193,8 +5257,17 @@ static void event_hist_trigger(struct event_trigger_data *data,
 
 		if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
 			memset(entries, 0, HIST_STACKTRACE_SIZE);
-			stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
-					 HIST_STACKTRACE_SKIP);
+			if (key_field->field) {
+				unsigned long *stack, n_entries;
+
+				field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
+				stack = (unsigned long *)(long)field_contents;
+				n_entries = *stack;
+				memcpy(entries, ++stack, n_entries * sizeof(unsigned long));
+			} else {
+				stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
+						 HIST_STACKTRACE_SKIP);
+			}
 			key = entries;
 		} else {
 			field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
@@ -5297,7 +5370,10 @@ static void hist_trigger_print_key(struct seq_file *m,
 			seq_printf(m, "%s: %-30s[%3llu]", field_name,
 				   syscall_name, uval);
 		} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
-			seq_puts(m, "stacktrace:\n");
+			if (key_field->field)
+				seq_printf(m, "%s.stacktrace", key_field->field->name);
+			else
+				seq_puts(m, "stacktrace:\n");
 			hist_trigger_stacktrace_print(m,
 						      key + key_field->offset,
 						      HIST_STACKTRACE_DEPTH);
@@ -5842,7 +5918,8 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
 
 	if (hist_field->flags) {
 		if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
-		    !(hist_field->flags & HIST_FIELD_FL_EXPR)) {
+		    !(hist_field->flags & HIST_FIELD_FL_EXPR) &&
+		    !(hist_field->flags & HIST_FIELD_FL_STACKTRACE)) {
 			const char *flags = get_hist_field_flags(hist_field);
 
 			if (flags)
@@ -5875,9 +5952,12 @@ static int event_hist_trigger_print(struct seq_file *m,
 		if (i > hist_data->n_vals)
 			seq_puts(m, ",");
 
-		if (field->flags & HIST_FIELD_FL_STACKTRACE)
-			seq_puts(m, "stacktrace");
-		else
+		if (field->flags & HIST_FIELD_FL_STACKTRACE) {
+			if (field->field)
+				seq_printf(m, "%s.stacktrace", field->field->name);
+			else
+				seq_puts(m, "stacktrace");
+		} else
 			hist_field_print(m, field);
 	}