ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/net/mac80211/debugfs_key.h b/net/mac80211/debugfs_key.h
new file mode 100644
index 000000000..e17a48d5c
--- /dev/null
+++ b/net/mac80211/debugfs_key.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __MAC80211_DEBUGFS_KEY_H
+#define __MAC80211_DEBUGFS_KEY_H
+
+#ifdef CONFIG_MAC80211_DEBUGFS
+void ieee80211_debugfs_key_add(struct ieee80211_key *key);
+void ieee80211_debugfs_key_remove(struct ieee80211_key *key);
+void ieee80211_debugfs_key_update_default(struct ieee80211_sub_if_data *sdata);
+void ieee80211_debugfs_key_remove_mgmt_default(
+	struct ieee80211_sub_if_data *sdata);
+void ieee80211_debugfs_key_remove_beacon_default(
+	struct ieee80211_sub_if_data *sdata);
+#else
+static inline void ieee80211_debugfs_key_add(struct ieee80211_key *key)
+{}
+static inline void ieee80211_debugfs_key_remove(struct ieee80211_key *key)
+{}
+static inline void ieee80211_debugfs_key_update_default(
+	struct ieee80211_sub_if_data *sdata)
+{}
+static inline void ieee80211_debugfs_key_remove_mgmt_default(
+	struct ieee80211_sub_if_data *sdata)
+{}
+static inline void ieee80211_debugfs_key_remove_beacon_default(
+	struct ieee80211_sub_if_data *sdata)
+{}
+#endif
+
+#endif /* __MAC80211_DEBUGFS_KEY_H */