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, 343 insertions, 0 deletions

diff --git a/fs/hfsplus/bfind.c b/fs/hfsplus/bfind.c
new file mode 100644
index 000000000..ca9813f58
--- /dev/null
+++ b/fs/hfsplus/bfind.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/hfsplus/bfind.c
+ *
+ * Copyright (C) 2001
+ * Brad Boyer (flar@allandria.com)
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ * Search routines for btrees
+ */
+
+#include <linux/slab.h>
+#include "hfsplus_fs.h"
+
+int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
+{
+	void *ptr;
+
+	fd->tree = tree;
+	fd->bnode = NULL;
+	hfs_find_result_init(fd);
+	ptr = kzalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+	fd->search_key = ptr;
+	fd->key = ptr + tree->max_key_len + 2;
+	hfs_dbg("cnid %d, caller %ps\n",
+		tree->cnid, __builtin_return_address(0));
+	mutex_lock_nested(&tree->tree_lock,
+			hfsplus_btree_lock_class(tree));
+	return 0;
+}
+
+void hfs_find_exit(struct hfs_find_data *fd)
+{
+	hfs_bnode_put(fd->bnode);
+	kfree(fd->search_key);
+	hfs_dbg("cnid %d, caller %ps\n",
+		fd->tree->cnid, __builtin_return_address(0));
+	mutex_unlock(&fd->tree->tree_lock);
+	fd->tree = NULL;
+}
+
+int hfs_find_1st_rec_by_cnid(struct hfs_bnode *bnode,
+				struct hfs_find_data *fd,
+				int *begin,
+				int *end,
+				int *cur_rec)
+{
+	__be32 cur_cnid;
+	__be32 search_cnid;
+
+	if (bnode->tree->cnid == HFSPLUS_EXT_CNID) {
+		cur_cnid = fd->key->ext.cnid;
+		search_cnid = fd->search_key->ext.cnid;
+	} else if (bnode->tree->cnid == HFSPLUS_CAT_CNID) {
+		cur_cnid = fd->key->cat.parent;
+		search_cnid = fd->search_key->cat.parent;
+	} else if (bnode->tree->cnid == HFSPLUS_ATTR_CNID) {
+		cur_cnid = fd->key->attr.cnid;
+		search_cnid = fd->search_key->attr.cnid;
+	} else {
+		cur_cnid = 0;	/* used-uninitialized warning */
+		search_cnid = 0;
+		BUG();
+	}
+
+	if (cur_cnid == search_cnid) {
+		(*end) = (*cur_rec);
+		if ((*begin) == (*end))
+			return 1;
+	} else {
+		if (be32_to_cpu(cur_cnid) < be32_to_cpu(search_cnid))
+			(*begin) = (*cur_rec) + 1;
+		else
+			(*end) = (*cur_rec) - 1;
+	}
+
+	return 0;
+}
+
+int hfs_find_rec_by_key(struct hfs_bnode *bnode,
+				struct hfs_find_data *fd,
+				int *begin,
+				int *end,
+				int *cur_rec)
+{
+	int cmpval;
+
+	cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
+	if (!cmpval) {
+		(*end) = (*cur_rec);
+		return 1;
+	}
+	if (cmpval < 0)
+		(*begin) = (*cur_rec) + 1;
+	else
+		*(end) = (*cur_rec) - 1;
+
+	return 0;
+}
+
+/* Find the record in bnode that best matches key (not greater than...)*/
+int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd,
+					search_strategy_t rec_found)
+{
+	u16 off, len, keylen;
+	int rec;
+	int b, e;
+	int res = -ENOENT;
+
+	BUG_ON(!rec_found);
+	hfs_find_result_init(fd);
+	if (hfs_bnode_num_recs_invalid(bnode))
+		goto fail;
+
+	b = 0;
+	e = bnode->num_recs - 1;
+	do {
+		rec = (e + b) / 2;
+		len = hfs_brec_lenoff(bnode, rec, &off);
+		keylen = hfs_brec_keylen(bnode, rec);
+		if (hfs_brec_len_invalid(bnode, len) ||
+		    hfs_brec_len_invalid(bnode, keylen)) {
+			res = -EINVAL;
+			goto fail;
+		}
+		hfs_bnode_read(bnode, fd->key, off, keylen);
+		if (rec_found(bnode, fd, &b, &e, &rec)) {
+			res = 0;
+			goto done;
+		}
+	} while (b <= e);
+
+	if (rec != e && e >= 0) {
+		len = hfs_brec_lenoff(bnode, e, &off);
+		keylen = hfs_brec_keylen(bnode, e);
+		if (hfs_brec_len_invalid(bnode, keylen) ||
+		    hfs_brec_len_invalid(bnode, len)) {
+			res = -EINVAL;
+			goto fail;
+		}
+		hfs_bnode_read(bnode, fd->key, off, keylen);
+	}
+
+done:
+	fd->record = e;
+	fd->keyoffset = off;
+	fd->keylength = keylen;
+	fd->entryoffset = off + keylen;
+	fd->entrylength = len - keylen;
+
+fail:
+	return res;
+}
+
+/* Traverse a B*Tree from the root to a leaf finding best fit to key */
+/* Return allocated copy of node found, set recnum to best record */
+int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare)
+{
+	struct hfs_btree *tree;
+	struct hfs_bnode *bnode;
+	u32 nidx, parent;
+	__be32 data;
+	int height, res;
+
+	hfs_find_result_init(fd);
+
+	tree = fd->tree;
+	if (fd->bnode)
+		hfs_bnode_put(fd->bnode);
+	fd->bnode = NULL;
+	nidx = tree->root;
+	if (!nidx)
+		return -ENOENT;
+	height = tree->depth;
+	res = 0;
+	parent = 0;
+	for (;;) {
+		bnode = hfs_bnode_find(tree, nidx);
+		if (IS_ERR(bnode)) {
+			res = PTR_ERR(bnode);
+			bnode = NULL;
+			break;
+		}
+		if (bnode->height != height)
+			goto invalid;
+		if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF))
+			goto invalid;
+		bnode->parent = parent;
+
+		res = __hfs_brec_find(bnode, fd, do_key_compare);
+		if (!height)
+			break;
+		if (fd->record < 0)
+			goto release;
+
+		parent = nidx;
+		hfs_bnode_read(bnode, &data, fd->entryoffset, 4);
+		nidx = be32_to_cpu(data);
+		hfs_bnode_put(bnode);
+	}
+	fd->bnode = bnode;
+	return res;
+
+invalid:
+	pr_err("inconsistency in B*Tree (%d,%d,%d,%u,%u)\n",
+		height, bnode->height, bnode->type, nidx, parent);
+	res = -EIO;
+release:
+	hfs_bnode_put(bnode);
+	return res;
+}
+
+int hfs_brec_read(struct hfs_find_data *fd, void *rec, u32 rec_len)
+{
+	int res;
+
+	res = hfs_brec_find(fd, hfs_find_rec_by_key);
+	if (res)
+		return res;
+	if (fd->entrylength > rec_len)
+		return -EINVAL;
+	hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength);
+	return 0;
+}
+
+int hfs_brec_goto(struct hfs_find_data *fd, int cnt)
+{
+	struct hfs_btree *tree;
+	struct hfs_bnode *bnode;
+	int idx, res = 0;
+	u16 off, len, keylen;
+
+	bnode = fd->bnode;
+	tree = bnode->tree;
+
+	if (cnt < 0) {
+		cnt = -cnt;
+		while (cnt > fd->record) {
+			cnt -= fd->record + 1;
+			fd->record = bnode->num_recs - 1;
+			idx = bnode->prev;
+			if (!idx) {
+				res = -ENOENT;
+				goto out;
+			}
+			hfs_bnode_put(bnode);
+			bnode = hfs_bnode_find(tree, idx);
+			if (IS_ERR(bnode)) {
+				res = PTR_ERR(bnode);
+				bnode = NULL;
+				goto out;
+			}
+		}
+		fd->record -= cnt;
+	} else {
+		while (cnt >= bnode->num_recs - fd->record) {
+			cnt -= bnode->num_recs - fd->record;
+			fd->record = 0;
+			idx = bnode->next;
+			if (!idx) {
+				res = -ENOENT;
+				goto out;
+			}
+			hfs_bnode_put(bnode);
+			bnode = hfs_bnode_find(tree, idx);
+			if (IS_ERR(bnode)) {
+				res = PTR_ERR(bnode);
+				bnode = NULL;
+				goto out;
+			}
+		}
+		fd->record += cnt;
+	}
+
+	len = hfs_brec_lenoff(bnode, fd->record, &off);
+	keylen = hfs_brec_keylen(bnode, fd->record);
+	if (hfs_brec_len_invalid(bnode, len) ||
+	    hfs_brec_len_invalid(bnode, keylen)) {
+		res = -EINVAL;
+		goto out;
+	}
+	fd->keyoffset = off;
+	fd->keylength = keylen;
+	fd->entryoffset = off + keylen;
+	fd->entrylength = len - keylen;
+	hfs_bnode_read(bnode, fd->key, off, keylen);
+out:
+	fd->bnode = bnode;
+	return res;
+}
+
+/**
+ * hfsplus_brec_read_cat - read and validate a catalog record
+ * @fd: find data structure
+ * @entry: pointer to catalog entry to read into
+ *
+ * Reads a catalog record and validates its size matches the expected
+ * size based on the record type.
+ *
+ * Returns 0 on success, or negative error code on failure.
+ */
+int hfsplus_brec_read_cat(struct hfs_find_data *fd, hfsplus_cat_entry *entry)
+{
+	int res;
+	u32 expected_size;
+
+	res = hfs_brec_read(fd, entry, sizeof(hfsplus_cat_entry));
+	if (res)
+		return res;
+
+	/* Validate catalog record size based on type */
+	switch (be16_to_cpu(entry->type)) {
+	case HFSPLUS_FOLDER:
+		expected_size = sizeof(struct hfsplus_cat_folder);
+		break;
+	case HFSPLUS_FILE:
+		expected_size = sizeof(struct hfsplus_cat_file);
+		break;
+	case HFSPLUS_FOLDER_THREAD:
+	case HFSPLUS_FILE_THREAD:
+		/* Ensure we have at least the fixed fields before reading nodeName.length */
+		if (fd->entrylength < HFSPLUS_MIN_THREAD_SZ) {
+			pr_err("thread record too short (got %u)\n", fd->entrylength);
+			return -EIO;
+		}
+		expected_size = hfsplus_cat_thread_size(&entry->thread);
+		break;
+	default:
+		pr_err("unknown catalog record type %d\n",
+		       be16_to_cpu(entry->type));
+		return -EIO;
+	}
+
+	if (fd->entrylength != expected_size) {
+		pr_err("catalog record size mismatch (type %d, got %u, expected %u)\n",
+		       be16_to_cpu(entry->type), fd->entrylength, expected_size);
+		return -EIO;
+	}
+
+	return 0;
+}