trace-cmd: Initialize option list earlier in create_file_fd()

Commit Message

Steven Rostedt June 22, 2021, 2:18 a.m. UTC

From: "Steven Rostedt (VMware)" <[e-mail]>

The error paths of create_file_fd() after the handle is allocated, jumps
to the out_free label. This will call tracecmd_output_close(), which will
clean up the allocated tracecmd_output handle. This includes the options
list. But there's two error paths that will jump to out_free before the
options list is initialized. If an error occurs in one of these two
locations, then walking the option list will cause a segfault.

Initialize the option list immediately after the allocation of the handle
and before any of the error paths that jump to out_free.

Signed-off-by: Steven Rostedt (VMware) <[e-mail]>
---
 lib/trace-cmd/trace-output.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Patch

diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index b3d0fe7e..78a25350 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -938,6 +938,8 @@  create_file_fd(int fd, struct tracecmd_input *ihandle,
 		return NULL;
 	memset(handle, 0, sizeof(*handle));
 
+	list_head_init(&handle->options);
+
 	handle->fd = fd;
 	if (tracing_dir) {
 		handle->tracing_dir = strdup(tracing_dir);
@@ -950,8 +952,6 @@  create_file_fd(int fd, struct tracecmd_input *ihandle,
 	if (select_file_version(handle, ihandle))
 		goto out_free;
 
-	list_head_init(&handle->options);
-
 	buf[0] = 23;
 	buf[1] = 8;
 	buf[2] = 68;