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, 43 insertions, 0 deletions

diff --git a/fs/jffs2/acl.h b/fs/jffs2/acl.h
new file mode 100644
index 000000000..e976b8cb8
--- /dev/null
+++ b/fs/jffs2/acl.h
@@ -0,0 +1,43 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2006  NEC Corporation
+ *
+ * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+struct jffs2_acl_entry {
+	jint16_t	e_tag;
+	jint16_t	e_perm;
+	jint32_t	e_id;
+};
+
+struct jffs2_acl_entry_short {
+	jint16_t	e_tag;
+	jint16_t	e_perm;
+};
+
+struct jffs2_acl_header {
+	jint32_t	a_version;
+	struct jffs2_acl_entry	a_entries[];
+};
+
+#ifdef CONFIG_JFFS2_FS_POSIX_ACL
+
+struct posix_acl *jffs2_get_acl(struct inode *inode, int type, bool rcu);
+int jffs2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		  struct posix_acl *acl, int type);
+extern int jffs2_init_acl_pre(struct inode *, struct inode *, umode_t *);
+extern int jffs2_init_acl_post(struct inode *);
+
+#else
+
+#define jffs2_get_acl				(NULL)
+#define jffs2_set_acl				(NULL)
+#define jffs2_init_acl_pre(dir_i,inode,mode)	(0)
+#define jffs2_init_acl_post(inode)		(0)
+
+#endif	/* CONFIG_JFFS2_FS_POSIX_ACL */