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, 158 insertions, 0 deletions

diff --git a/fs/ntfs/object_id.c b/fs/ntfs/object_id.c
new file mode 100644
index 000000000..89002c375
--- /dev/null
+++ b/fs/ntfs/object_id.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Pocessing of object ids
+ *
+ * Part of this file is based on code from the NTFS-3G.
+ *
+ * Copyright (c) 2009-2019 Jean-Pierre Andre
+ * Copyright (c) 2026 LG Electronics Co., Ltd.
+ */
+
+#include "ntfs.h"
+#include "index.h"
+#include "object_id.h"
+
+struct object_id_index_key {
+	union {
+		u32 alignment;
+		struct guid guid;
+	} object_id;
+} __packed;
+
+struct object_id_index_data {
+	__le64 file_id;
+	struct guid birth_volume_id;
+	struct guid birth_object_id;
+	struct guid domain_id;
+} __packed;
+
+/* Index entry in $Extend/$ObjId */
+struct object_id_index {
+	struct index_entry_header header;
+	struct object_id_index_key key;
+	struct object_id_index_data data;
+} __packed;
+
+__le16 objid_index_name[] = {cpu_to_le16('$'), cpu_to_le16('O'), 0};
+
+/*
+ * open_object_id_index - Open the $Extend/$ObjId file and its index
+ * @vol: NTFS volume structure
+ *
+ * Opens the $ObjId system file and retrieves its index context.
+ *
+ * Return: The index context if opened successfully, or NULL if an error
+ *	   occurred.
+ */
+static struct ntfs_index_context *open_object_id_index(struct ntfs_volume *vol)
+{
+	struct inode *dir_vi, *vi;
+	struct ntfs_inode *dir_ni;
+	struct ntfs_index_context *xo = NULL;
+	struct ntfs_name *name = NULL;
+	u64 mref;
+	int uname_len;
+	__le16 *uname;
+
+	uname_len = ntfs_nlstoucs(vol, "$ObjId", 6, &uname,
+			NTFS_MAX_NAME_LEN);
+	if (uname_len < 0)
+		return NULL;
+
+	/* do not use path_name_to inode - could reopen root */
+	dir_vi = ntfs_iget(vol->sb, FILE_Extend);
+	if (IS_ERR(dir_vi)) {
+		kmem_cache_free(ntfs_name_cache, uname);
+		return NULL;
+	}
+	dir_ni = NTFS_I(dir_vi);
+
+	mutex_lock_nested(&dir_ni->mrec_lock, NTFS_EXTEND_MUTEX_PARENT);
+	mref = ntfs_lookup_inode_by_name(dir_ni, uname, uname_len, &name);
+	mutex_unlock(&dir_ni->mrec_lock);
+	kfree(name);
+	kmem_cache_free(ntfs_name_cache, uname);
+	if (IS_ERR_MREF(mref))
+		goto put_dir_vi;
+
+	vi = ntfs_iget(vol->sb, MREF(mref));
+	if (IS_ERR(vi))
+		goto put_dir_vi;
+
+	xo = ntfs_index_ctx_get(NTFS_I(vi), objid_index_name, 2);
+	if (!xo)
+		iput(vi);
+put_dir_vi:
+	iput(dir_vi);
+	return xo;
+}
+
+
+/*
+ * remove_object_id_index - Remove an object id index entry if attribute present
+ * @ni: NTFS inode structure containing the attribute
+ * @xo:	Index context for the object id index
+ *
+ * Reads the existing object ID attribute and removes it from the index.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+static int remove_object_id_index(struct ntfs_inode *ni, struct ntfs_index_context *xo)
+{
+	struct object_id_index_key key = {0};
+	s64 size;
+
+	if (ni->data_size == 0)
+		return -ENODATA;
+
+	/* read the existing object id attribute */
+	size = ntfs_inode_attr_pread(VFS_I(ni), 0, sizeof(struct guid),
+				     (char *)&key);
+	if (size != sizeof(struct guid))
+		return -ENODATA;
+
+	if (!ntfs_index_lookup(&key, sizeof(struct object_id_index_key), xo))
+		return ntfs_index_rm(xo);
+
+	return 0;
+}
+
+/*
+ * ntfs_delete_object_id_index - Delete an object_id index entry
+ * @ni:	NTFS inode structure
+ *
+ * Opens the object ID index and removes the entry corresponding to the inode.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int ntfs_delete_object_id_index(struct ntfs_inode *ni)
+{
+	struct ntfs_index_context *xo;
+	struct ntfs_inode *xoni;
+	struct inode *attr_vi;
+	int ret = 0;
+
+	attr_vi = ntfs_attr_iget(VFS_I(ni), AT_OBJECT_ID, AT_UNNAMED, 0);
+	if (IS_ERR(attr_vi))
+		return PTR_ERR(attr_vi);
+
+	/*
+	 * read the existing object id and un-index it
+	 */
+	xo = open_object_id_index(ni->vol);
+	if (xo) {
+		xoni = xo->idx_ni;
+		mutex_lock_nested(&xoni->mrec_lock, NTFS_EXTEND_MUTEX_PARENT);
+		ret = remove_object_id_index(NTFS_I(attr_vi), xo);
+		if (!ret) {
+			ntfs_index_entry_mark_dirty(xo);
+			mark_mft_record_dirty(xoni);
+		}
+		ntfs_index_ctx_put(xo);
+		mutex_unlock(&xoni->mrec_lock);
+		iput(VFS_I(xoni));
+	}
+
+	iput(attr_vi);
+	return ret;
+}