[PATCH v3 12/21] trace-cmd library: Fix possible memory leak in read_ftrace_printk()

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

Some error paths in read_ftrace_printk() may lead to a memory leak.
Improved the error handling of this internal function to avoid it.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-input.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 9b23063e..60d75d47 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -777,33 +777,39 @@ out:
 static int read_ftrace_printk(struct tracecmd_input *handle)
 {
 	unsigned int size;
-	char *buf;
+	char *buf = NULL;
+	int ret;
 
 	if (handle->file_state >= TRACECMD_FILE_PRINTK)
 		return 0;
 
-	if (read4(handle, &size) < 0)
-		return -1;
-	if (!size)
-		return 0; /* OK? */
+	ret = read4(handle, &size);
+	if (ret < 0)
+		goto out;
+	if (!size) {
+		handle->file_state = TRACECMD_FILE_PRINTK;
+		goto out; /* OK? */
+	}
 
 	buf = malloc(size + 1);
-	if (!buf)
-		return -1;
-	if (do_read_check(handle, buf, size)) {
-		free(buf);
-		return -1;
+	if (!buf) {
+		ret = -1;
+		goto out;
 	}
+	ret = do_read_check(handle, buf, size);
+	if (ret < 0)
+		goto out;
 
 	buf[size] = 0;
 
 	tep_parse_printk_formats(handle->pevent, buf);
 
-	free(buf);
-
 	handle->file_state = TRACECMD_FILE_PRINTK;
+	ret = 0;
 
-	return 0;
+out:
+	free(buf);
+	return ret;
 }
 
 static int read_and_parse_cmdlines(struct tracecmd_input *handle);
-- 
2.31.1