ftrace: Initialize variables for ftrace_startup/shutdown_subops()

Commit Message

Steven Rostedt April 17, 2025, 2:40 p.m. UTC

From: Steven Rostedt <[e-mail]>

The reworking to fix and simplify the ftrace_startup_subops() and the
ftrace_shutdown_subops() made it possible for the filter_hash and
notrace_hash variables to be used uninitialized in a way that the compiler
did not catch it.

Initialize both filter_hash and notrace_hash to the EMPTY_HASH as that is
what they should be if they never are used.

Reported-by: Venkat Rao Bagalkote <[e-mail]>
Tested-by: Venkat Rao Bagalkote <[e-mail]>
Fixes: 0ae6b8ce200d ("ftrace: Fix accounting of subop hashes")
Closes: https://lore.kernel.org/all/[e-mail]/
Signed-off-by: Steven Rostedt (Google) <[e-mail]>
---
 kernel/trace/ftrace.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Patch

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 19b902b8de2b..66bf4512ec04 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3490,8 +3490,8 @@  static int add_next_hash(struct ftrace_hash **filter_hash, struct ftrace_hash **
  */
 int ftrace_startup_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int command)
 {
-	struct ftrace_hash *filter_hash;
-	struct ftrace_hash *notrace_hash;
+	struct ftrace_hash *filter_hash = EMPTY_HASH;
+	struct ftrace_hash *notrace_hash = EMPTY_HASH;
 	struct ftrace_hash *save_filter_hash;
 	struct ftrace_hash *save_notrace_hash;
 	int ret;
@@ -3625,8 +3625,8 @@  static int rebuild_hashes(struct ftrace_hash **filter_hash, struct ftrace_hash *
  */
 int ftrace_shutdown_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int command)
 {
-	struct ftrace_hash *filter_hash;
-	struct ftrace_hash *notrace_hash;
+	struct ftrace_hash *filter_hash = EMPTY_HASH;
+	struct ftrace_hash *notrace_hash = EMPTY_HASH;
 	int ret;
 
 	if (unlikely(ftrace_disabled))