---

yaml
---
r: 338996
b: refs/heads/master
c: 7ffbd48
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2b70e59043f5a5ec083ea50cd2640aa49c64c675
+refs/heads/master: 7ffbd48d5cab22bcd1120eb2349db1319e2d827a

trunk/kernel/trace/trace.c

@@ -77,6 +77,13 @@ static int dummy_set_flag(u32 old_flags, u32 bit, int set)
 	return 0;
 }
 
+/*
+ * To prevent the comm cache from being overwritten when no
+ * tracing is active, only save the comm when a trace event
+ * occurred.
+ */
+static DEFINE_PER_CPU(bool, trace_cmdline_save);
+
 /*
  * Kill all tracing for good (never come back).
  * It is initialized to 1 but will turn to zero if the initialization
@@ -1135,6 +1142,11 @@ void tracing_record_cmdline(struct task_struct *tsk)
 	    !tracing_is_on())
 		return;
 
+	if (!__this_cpu_read(trace_cmdline_save))
+		return;
+
+	__this_cpu_write(trace_cmdline_save, false);
+
 	trace_save_cmdline(tsk);
 }
 
@@ -1178,13 +1190,20 @@ trace_buffer_lock_reserve(struct ring_buffer *buffer,
 	return event;
 }
 
+void
+__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
+{
+	__this_cpu_write(trace_cmdline_save, true);
+	ring_buffer_unlock_commit(buffer, event);
+}
+
 static inline void
 __trace_buffer_unlock_commit(struct ring_buffer *buffer,
 			     struct ring_buffer_event *event,
 			     unsigned long flags, int pc,
 			     int wake)
 {
-	ring_buffer_unlock_commit(buffer, event);
+	__buffer_unlock_commit(buffer, event);
 
 	ftrace_trace_stack(buffer, flags, 6, pc);
 	ftrace_trace_userstack(buffer, flags, pc);
@@ -1232,7 +1251,7 @@ void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer *buffer,
 					    unsigned long flags, int pc,
 					    struct pt_regs *regs)
 {
-	ring_buffer_unlock_commit(buffer, event);
+	__buffer_unlock_commit(buffer, event);
 
 	ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
 	ftrace_trace_userstack(buffer, flags, pc);
@@ -1269,7 +1288,7 @@ trace_function(struct trace_array *tr,
 	entry->parent_ip		= parent_ip;
 
 	if (!filter_check_discard(call, entry, buffer, event))
-		ring_buffer_unlock_commit(buffer, event);
+		__buffer_unlock_commit(buffer, event);
 }
 
 void
@@ -1362,7 +1381,7 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer,
 	entry->size = trace.nr_entries;
 
 	if (!filter_check_discard(call, entry, buffer, event))
-		ring_buffer_unlock_commit(buffer, event);
+		__buffer_unlock_commit(buffer, event);
 
  out:
 	/* Again, don't let gcc optimize things here */
@@ -1458,7 +1477,7 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 
 	save_stack_trace_user(&trace);
 	if (!filter_check_discard(call, entry, buffer, event))
-		ring_buffer_unlock_commit(buffer, event);
+		__buffer_unlock_commit(buffer, event);
 
  out_drop_count:
 	__this_cpu_dec(user_stack_count);
@@ -1653,7 +1672,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 
 	memcpy(entry->buf, tbuffer, sizeof(u32) * len);
 	if (!filter_check_discard(call, entry, buffer, event)) {
-		ring_buffer_unlock_commit(buffer, event);
+		__buffer_unlock_commit(buffer, event);
 		ftrace_trace_stack(buffer, flags, 6, pc);
 	}
 
@@ -1724,7 +1743,7 @@ int trace_array_vprintk(struct trace_array *tr,
 	memcpy(&entry->buf, tbuffer, len);
 	entry->buf[len] = '\0';
 	if (!filter_check_discard(call, entry, buffer, event)) {
-		ring_buffer_unlock_commit(buffer, event);
+		__buffer_unlock_commit(buffer, event);
 		ftrace_trace_stack(buffer, flags, 6, pc);
 	}
  out:
@@ -3993,7 +4012,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 	} else
 		entry->buf[cnt] = '\0';
 
-	ring_buffer_unlock_commit(buffer, event);
+	__buffer_unlock_commit(buffer, event);
 
 	written = cnt;
 

trunk/kernel/trace/trace.h

@@ -359,6 +359,9 @@ struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 					  int *ent_cpu, u64 *ent_ts);
 
+void __buffer_unlock_commit(struct ring_buffer *buffer,
+			    struct ring_buffer_event *event);
+
 int trace_empty(struct trace_iterator *iter);
 
 void *trace_find_next_entry_inc(struct trace_iterator *iter);

trunk/kernel/trace/trace_branch.c

@@ -77,7 +77,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
 	entry->correct = val == expect;
 
 	if (!filter_check_discard(call, entry, buffer, event))
-		ring_buffer_unlock_commit(buffer, event);
+		__buffer_unlock_commit(buffer, event);
 
  out:
 	atomic_dec(&tr->data[cpu]->disabled);

trunk/kernel/trace/trace_functions_graph.c

@@ -223,7 +223,7 @@ int __trace_graph_entry(struct trace_array *tr,
 	entry	= ring_buffer_event_data(event);
 	entry->graph_ent			= *trace;
 	if (!filter_current_check_discard(buffer, call, entry, event))
-		ring_buffer_unlock_commit(buffer, event);
+		__buffer_unlock_commit(buffer, event);
 
 	return 1;
 }
@@ -327,7 +327,7 @@ void __trace_graph_return(struct trace_array *tr,
 	entry	= ring_buffer_event_data(event);
 	entry->ret				= *trace;
 	if (!filter_current_check_discard(buffer, call, entry, event))
-		ring_buffer_unlock_commit(buffer, event);
+		__buffer_unlock_commit(buffer, event);
 }
 
 void trace_graph_return(struct ftrace_graph_ret *trace)