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, 153 insertions, 0 deletions

diff --git a/fs/hfs/attr.c b/fs/hfs/attr.c
new file mode 100644
index 000000000..f8395cdd1
--- /dev/null
+++ b/fs/hfs/attr.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/hfs/attr.c
+ *
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ * Export hfs data via xattr
+ */
+
+
+#include <linux/fs.h>
+#include <linux/xattr.h>
+
+#include "hfs_fs.h"
+#include "btree.h"
+
+enum hfs_xattr_type {
+	HFS_TYPE,
+	HFS_CREATOR,
+};
+
+static int __hfs_setxattr(struct inode *inode, enum hfs_xattr_type type,
+			  const void *value, size_t size, int flags)
+{
+	struct hfs_find_data fd;
+	hfs_cat_rec rec;
+	struct hfs_cat_file *file;
+	int res;
+
+	if (!S_ISREG(inode->i_mode) || HFS_IS_RSRC(inode))
+		return -EOPNOTSUPP;
+
+	res = hfs_find_init(HFS_SB(inode->i_sb)->cat_tree, &fd);
+	if (res)
+		return res;
+	fd.search_key->cat = HFS_I(inode)->cat_key;
+	res = hfs_brec_find(&fd);
+	if (res)
+		goto out;
+	hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
+			sizeof(struct hfs_cat_file));
+	file = &rec.file;
+
+	switch (type) {
+	case HFS_TYPE:
+		if (size == 4)
+			memcpy(&file->UsrWds.fdType, value, 4);
+		else
+			res = -ERANGE;
+		break;
+
+	case HFS_CREATOR:
+		if (size == 4)
+			memcpy(&file->UsrWds.fdCreator, value, 4);
+		else
+			res = -ERANGE;
+		break;
+	}
+
+	if (!res)
+		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
+				sizeof(struct hfs_cat_file));
+out:
+	hfs_find_exit(&fd);
+	return res;
+}
+
+static ssize_t __hfs_getxattr(struct inode *inode, enum hfs_xattr_type type,
+			      void *value, size_t size)
+{
+	struct hfs_find_data fd;
+	hfs_cat_rec rec;
+	struct hfs_cat_file *file;
+	ssize_t res = 0;
+
+	if (!S_ISREG(inode->i_mode) || HFS_IS_RSRC(inode))
+		return -EOPNOTSUPP;
+
+	if (size) {
+		res = hfs_find_init(HFS_SB(inode->i_sb)->cat_tree, &fd);
+		if (res)
+			return res;
+		fd.search_key->cat = HFS_I(inode)->cat_key;
+		res = hfs_brec_find(&fd);
+		if (res)
+			goto out;
+		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
+				sizeof(struct hfs_cat_file));
+	}
+	file = &rec.file;
+
+	switch (type) {
+	case HFS_TYPE:
+		if (size >= 4) {
+			memcpy(value, &file->UsrWds.fdType, 4);
+			res = 4;
+		} else
+			res = size ? -ERANGE : 4;
+		break;
+
+	case HFS_CREATOR:
+		if (size >= 4) {
+			memcpy(value, &file->UsrWds.fdCreator, 4);
+			res = 4;
+		} else
+			res = size ? -ERANGE : 4;
+		break;
+	}
+
+out:
+	if (size)
+		hfs_find_exit(&fd);
+	return res;
+}
+
+static int hfs_xattr_get(const struct xattr_handler *handler,
+			 struct dentry *unused, struct inode *inode,
+			 const char *name, void *value, size_t size)
+{
+	return __hfs_getxattr(inode, handler->flags, value, size);
+}
+
+static int hfs_xattr_set(const struct xattr_handler *handler,
+			 struct mnt_idmap *idmap,
+			 struct dentry *unused, struct inode *inode,
+			 const char *name, const void *value, size_t size,
+			 int flags)
+{
+	if (!value)
+		return -EOPNOTSUPP;
+
+	return __hfs_setxattr(inode, handler->flags, value, size, flags);
+}
+
+static const struct xattr_handler hfs_creator_handler = {
+	.name = "hfs.creator",
+	.flags = HFS_CREATOR,
+	.get = hfs_xattr_get,
+	.set = hfs_xattr_set,
+};
+
+static const struct xattr_handler hfs_type_handler = {
+	.name = "hfs.type",
+	.flags = HFS_TYPE,
+	.get = hfs_xattr_get,
+	.set = hfs_xattr_set,
+};
+
+const struct xattr_handler * const hfs_xattr_handlers[] = {
+	&hfs_creator_handler,
+	&hfs_type_handler,
+	NULL
+};