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, 331 insertions, 0 deletions

diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
new file mode 100644
index 000000000..e1f1fb351
--- /dev/null
+++ b/fs/hfs/dir.c
@@ -0,0 +1,331 @@
+/*
+ *  linux/fs/hfs/dir.c
+ *
+ * Copyright (C) 1995-1997  Paul H. Hargrove
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ * This file may be distributed under the terms of the GNU General Public License.
+ *
+ * This file contains directory-related functions independent of which
+ * scheme is being used to represent forks.
+ *
+ * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
+ */
+
+#include "hfs_fs.h"
+#include "btree.h"
+
+/*
+ * hfs_lookup()
+ */
+static struct dentry *hfs_lookup(struct inode *dir, struct dentry *dentry,
+				 unsigned int flags)
+{
+	hfs_cat_rec rec;
+	struct hfs_find_data fd;
+	struct inode *inode = NULL;
+	int res;
+
+	res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
+	if (res)
+		return ERR_PTR(res);
+	hfs_cat_build_key(dir->i_sb, fd.search_key, dir->i_ino, &dentry->d_name);
+	res = hfs_brec_read(&fd, &rec, sizeof(rec));
+	if (res) {
+		if (res != -ENOENT)
+			inode = ERR_PTR(res);
+	} else {
+		inode = hfs_iget(dir->i_sb, &fd.search_key->cat, &rec);
+		if (!inode)
+			inode = ERR_PTR(-EACCES);
+	}
+	hfs_find_exit(&fd);
+	return d_splice_alias(inode, dentry);
+}
+
+/*
+ * hfs_readdir
+ */
+static int hfs_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	int len, err;
+	char strbuf[HFS_MAX_NAMELEN];
+	union hfs_cat_rec entry;
+	struct hfs_find_data fd;
+	struct hfs_readdir_data *rd;
+	u16 type;
+
+	if (ctx->pos >= inode->i_size)
+		return 0;
+
+	err = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	if (err)
+		return err;
+	hfs_cat_build_key(sb, fd.search_key, inode->i_ino, NULL);
+	err = hfs_brec_find(&fd);
+	if (err)
+		goto out;
+
+	if (ctx->pos == 0) {
+		/* This is completely artificial... */
+		if (!dir_emit_dot(file, ctx))
+			goto out;
+		ctx->pos = 1;
+	}
+	if (ctx->pos == 1) {
+		if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) {
+			err = -EIO;
+			goto out;
+		}
+
+		hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);
+		if (entry.type != HFS_CDR_THD) {
+			pr_err("bad catalog folder thread\n");
+			err = -EIO;
+			goto out;
+		}
+		//if (fd.entrylength < HFS_MIN_THREAD_SZ) {
+		//	pr_err("truncated catalog thread\n");
+		//	err = -EIO;
+		//	goto out;
+		//}
+		if (!dir_emit(ctx, "..", 2,
+			    be32_to_cpu(entry.thread.ParID), DT_DIR))
+			goto out;
+		ctx->pos = 2;
+	}
+	if (ctx->pos >= inode->i_size)
+		goto out;
+	rd = file->private_data;
+	if (rd && rd->pos == ctx->pos) {
+		memcpy(fd.search_key, &rd->key, sizeof(struct hfs_cat_key));
+		err = hfs_brec_find(&fd);
+		if (err == -ENOENT)
+			err = hfs_brec_goto(&fd, 1);
+	} else {
+		err = hfs_brec_goto(&fd, ctx->pos - 1);
+	}
+	if (err)
+		goto out;
+
+	for (;;) {
+		if (be32_to_cpu(fd.key->cat.ParID) != inode->i_ino) {
+			pr_err("walked past end of dir\n");
+			err = -EIO;
+			goto out;
+		}
+
+		if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) {
+			err = -EIO;
+			goto out;
+		}
+
+		hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);
+		type = entry.type;
+		len = hfs_mac2asc(sb, strbuf, &fd.key->cat.CName);
+		if (type == HFS_CDR_DIR) {
+			if (fd.entrylength < sizeof(struct hfs_cat_dir)) {
+				pr_err("small dir entry\n");
+				err = -EIO;
+				goto out;
+			}
+			if (!dir_emit(ctx, strbuf, len,
+				    be32_to_cpu(entry.dir.DirID), DT_DIR))
+				break;
+		} else if (type == HFS_CDR_FIL) {
+			if (fd.entrylength < sizeof(struct hfs_cat_file)) {
+				pr_err("small file entry\n");
+				err = -EIO;
+				goto out;
+			}
+			if (!dir_emit(ctx, strbuf, len,
+				    be32_to_cpu(entry.file.FlNum), DT_REG))
+				break;
+		} else {
+			pr_err("bad catalog entry type %d\n", type);
+			err = -EIO;
+			goto out;
+		}
+		ctx->pos++;
+		if (ctx->pos >= inode->i_size)
+			goto out;
+		err = hfs_brec_goto(&fd, 1);
+		if (err)
+			goto out;
+	}
+	if (!rd) {
+		rd = kmalloc_obj(struct hfs_readdir_data);
+		if (!rd) {
+			err = -ENOMEM;
+			goto out;
+		}
+		file->private_data = rd;
+	}
+	rd->pos = ctx->pos;
+	memcpy(&rd->key, &fd.key->cat, sizeof(struct hfs_cat_key));
+out:
+	hfs_find_exit(&fd);
+	return err;
+}
+
+static int hfs_dir_release(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+	return 0;
+}
+
+/*
+ * hfs_create()
+ *
+ * This is the create() entry in the inode_operations structure for
+ * regular HFS directories.  The purpose is to create a new file in
+ * a directory and return a corresponding inode, given the inode for
+ * the directory and the name (and its length) of the new file.
+ */
+static int hfs_create(struct mnt_idmap *idmap, struct inode *dir,
+		      struct dentry *dentry, umode_t mode)
+{
+	struct inode *inode;
+	int res;
+
+	inode = hfs_new_inode(dir, &dentry->d_name, mode);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
+	if (res) {
+		clear_nlink(inode);
+		hfs_delete_inode(inode);
+		iput(inode);
+		return res;
+	}
+	d_instantiate(dentry, inode);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+/*
+ * hfs_mkdir()
+ *
+ * This is the mkdir() entry in the inode_operations structure for
+ * regular HFS directories.  The purpose is to create a new directory
+ * in a directory, given the inode for the parent directory and the
+ * name (and its length) of the new directory.
+ */
+static struct dentry *hfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
+				struct dentry *dentry, umode_t mode)
+{
+	struct inode *inode;
+	int res;
+
+	inode = hfs_new_inode(dir, &dentry->d_name, mode);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
+	res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
+	if (res) {
+		clear_nlink(inode);
+		hfs_delete_inode(inode);
+		iput(inode);
+		return ERR_PTR(res);
+	}
+	d_instantiate(dentry, inode);
+	mark_inode_dirty(inode);
+	return NULL;
+}
+
+/*
+ * hfs_remove()
+ *
+ * This serves as both unlink() and rmdir() in the inode_operations
+ * structure for regular HFS directories.  The purpose is to delete
+ * an existing child, given the inode for the parent directory and
+ * the name (and its length) of the existing directory.
+ *
+ * HFS does not have hardlinks, so both rmdir and unlink set the
+ * link count to 0.  The only difference is the emptiness check.
+ */
+static int hfs_remove(struct inode *dir, struct dentry *dentry)
+{
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode = d_inode(dentry);
+	int res;
+
+	if (S_ISDIR(inode->i_mode) && inode->i_size != 2)
+		return -ENOTEMPTY;
+
+	if (unlikely(!is_hfs_cnid_counts_valid(sb))) {
+	    pr_err("cannot remove file/folder\n");
+	    return -ERANGE;
+	}
+
+	res = hfs_cat_delete(inode->i_ino, dir, &dentry->d_name);
+	if (res)
+		return res;
+	clear_nlink(inode);
+	inode_set_ctime_current(inode);
+	hfs_delete_inode(inode);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+/*
+ * hfs_rename()
+ *
+ * This is the rename() entry in the inode_operations structure for
+ * regular HFS directories.  The purpose is to rename an existing
+ * file or directory, given the inode for the current directory and
+ * the name (and its length) of the existing file/directory and the
+ * inode for the new directory and the name (and its length) of the
+ * new file/directory.
+ * XXX: how do you handle must_be dir?
+ */
+static int hfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
+		      struct dentry *old_dentry, struct inode *new_dir,
+		      struct dentry *new_dentry, unsigned int flags)
+{
+	int res;
+
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	/* Unlink destination if it already exists */
+	if (d_really_is_positive(new_dentry)) {
+		res = hfs_remove(new_dir, new_dentry);
+		if (res)
+			return res;
+	}
+
+	res = hfs_cat_move(d_inode(old_dentry)->i_ino,
+			   old_dir, &old_dentry->d_name,
+			   new_dir, &new_dentry->d_name);
+	if (!res) {
+		struct inode *inode = d_inode(old_dentry);
+
+		hfs_cat_build_key(old_dir->i_sb,
+				  (btree_key *)&HFS_I(inode)->cat_key,
+				  new_dir->i_ino, &new_dentry->d_name);
+		inode_set_ctime_current(inode);
+		mark_inode_dirty(inode);
+	}
+	return res;
+}
+
+const struct file_operations hfs_dir_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= hfs_readdir,
+	.llseek		= generic_file_llseek,
+	.release	= hfs_dir_release,
+};
+
+const struct inode_operations hfs_dir_inode_operations = {
+	.create		= hfs_create,
+	.lookup		= hfs_lookup,
+	.unlink		= hfs_remove,
+	.mkdir		= hfs_mkdir,
+	.rmdir		= hfs_remove,
+	.rename		= hfs_rename,
+	.setattr	= hfs_inode_setattr,
+	.fileattr_get	= hfs_fileattr_get,
+};