1 files changed, 13 insertions, 8 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1f3ec2a..25edd5c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1662,7 +1662,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 
 	mutex_lock(&ftrace_regex_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND))
+	    (file->f_flags & O_TRUNC))
 		ftrace_filter_reset(enable);
 
 	if (file->f_mode & FMODE_READ) {
@@ -2278,7 +2278,11 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 	read++;
 	cnt--;
 
-	if (!(iter->flags & ~FTRACE_ITER_CONT)) {
+	/*
+	 * If the parser haven't finished with the last write,
+	 * continue reading the user input without skipping spaces.
+	 */
+	if (!(iter->flags & FTRACE_ITER_CONT)) {
 		/* skip white space */
 		while (cnt && isspace(ch)) {
 			ret = get_user(ch, ubuf++);
@@ -2288,8 +2292,9 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 			cnt--;
 		}
 
+		/* only spaces were written */
 		if (isspace(ch)) {
-			file->f_pos += read;
+			*ppos += read;
 			ret = read;
 			goto out;
 		}
@@ -2319,12 +2324,12 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 		if (ret)
 			goto out;
 		iter->buffer_idx = 0;
-	} else
+	} else {
 		iter->flags |= FTRACE_ITER_CONT;
+		iter->buffer[iter->buffer_idx++] = ch;
+	}
 
-
-	file->f_pos += read;
-
+	*ppos += read;
 	ret = read;
  out:
 	mutex_unlock(&ftrace_regex_lock);
@@ -2577,7 +2582,7 @@ ftrace_graph_open(struct inode *inode, struct file *file)
 
 	mutex_lock(&graph_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND)) {
+	    (file->f_flags & O_TRUNC)) {
 		ftrace_graph_count = 0;
 		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
 	}