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, 41 insertions, 0 deletions

diff --git a/fs/hfsplus/xattr.h b/fs/hfsplus/xattr.h
new file mode 100644
index 000000000..15cc55e41
--- /dev/null
+++ b/fs/hfsplus/xattr.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * linux/fs/hfsplus/xattr.h
+ *
+ * Vyacheslav Dubeyko <slava@dubeyko.com>
+ *
+ * Logic of processing extended attributes
+ */
+
+#ifndef _LINUX_HFSPLUS_XATTR_H
+#define _LINUX_HFSPLUS_XATTR_H
+
+#include <linux/xattr.h>
+
+extern const struct xattr_handler hfsplus_xattr_osx_handler;
+extern const struct xattr_handler hfsplus_xattr_user_handler;
+extern const struct xattr_handler hfsplus_xattr_trusted_handler;
+extern const struct xattr_handler hfsplus_xattr_security_handler;
+
+extern const struct xattr_handler * const hfsplus_xattr_handlers[];
+
+int __hfsplus_setxattr(struct inode *inode, const char *name,
+			const void *value, size_t size, int flags);
+
+int hfsplus_setxattr(struct inode *inode, const char *name,
+				   const void *value, size_t size, int flags,
+				   const char *prefix, size_t prefixlen);
+
+ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
+			   void *value, size_t size);
+
+ssize_t hfsplus_getxattr(struct inode *inode, const char *name,
+			 void *value, size_t size,
+			 const char *prefix, size_t prefixlen);
+
+ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size);
+
+int hfsplus_init_security(struct inode *inode, struct inode *dir,
+				const struct qstr *qstr);
+
+#endif