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, 32 insertions, 0 deletions

diff --git a/fs/ntfs/dir.h b/fs/ntfs/dir.h
new file mode 100644
index 000000000..a38c6b071
--- /dev/null
+++ b/fs/ntfs/dir.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Defines for directory handling in NTFS Linux kernel driver.
+ *
+ * Copyright (c) 2002-2004 Anton Altaparmakov
+ */
+
+#ifndef _LINUX_NTFS_DIR_H
+#define _LINUX_NTFS_DIR_H
+
+#include "inode.h"
+
+/*
+ * ntfs_name is used to return the file name to the caller of
+ * ntfs_lookup_inode_by_name() in order for the caller (namei.c::ntfs_lookup())
+ * to be able to deal with dcache aliasing issues.
+ */
+struct ntfs_name {
+	u64 mref;
+	u8 type;
+	u8 len;
+	__le16 name[];
+} __packed;
+
+/* The little endian Unicode string $I30 as a global constant. */
+extern __le16 I30[5];
+
+u64 ntfs_lookup_inode_by_name(struct ntfs_inode *dir_ni,
+		const __le16 *uname, const int uname_len, struct ntfs_name **res);
+int ntfs_check_empty_dir(struct ntfs_inode *ni, struct mft_record *ni_mrec);
+
+#endif /* _LINUX_NTFS_FS_DIR_H */