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, 50 insertions, 0 deletions

diff --git a/security/lsm.h b/security/lsm.h
new file mode 100644
index 000000000..32f808ad4
--- /dev/null
+++ b/security/lsm.h
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * LSM functions
+ */
+
+#ifndef _LSM_H_
+#define _LSM_H_
+
+#include <linux/printk.h>
+#include <linux/lsm_hooks.h>
+#include <linux/lsm_count.h>
+
+/* LSM debugging */
+extern bool lsm_debug;
+#define lsm_pr(...)		pr_info(__VA_ARGS__)
+#define lsm_pr_cont(...)	pr_cont(__VA_ARGS__)
+#define lsm_pr_dbg(...)							\
+	do {								\
+		if (lsm_debug)						\
+			pr_info(__VA_ARGS__);				\
+	} while (0)
+
+/* List of configured LSMs */
+extern unsigned int lsm_active_cnt;
+extern const struct lsm_id *lsm_idlist[];
+
+/* LSM blob configuration */
+extern struct lsm_blob_sizes blob_sizes;
+
+/* LSM blob caches */
+extern struct kmem_cache *lsm_file_cache;
+extern struct kmem_cache *lsm_backing_file_cache;
+extern struct kmem_cache *lsm_inode_cache;
+
+/* LSM blob allocators */
+int lsm_cred_alloc(struct cred *cred, gfp_t gfp);
+int lsm_task_alloc(struct task_struct *task);
+
+/* LSM framework initializers */
+
+#ifdef CONFIG_SECURITYFS
+int securityfs_init(void);
+#else
+static inline int securityfs_init(void)
+{
+	return 0;
+}
+#endif /* CONFIG_SECURITYFS */
+
+#endif /* _LSM_H_ */