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, 207 insertions, 0 deletions

diff --git a/security/tomoyo/memory.c b/security/tomoyo/memory.c
new file mode 100644
index 000000000..1b570bde7
--- /dev/null
+++ b/security/tomoyo/memory.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * security/tomoyo/memory.c
+ *
+ * Copyright (C) 2005-2011  NTT DATA CORPORATION
+ */
+
+#include <linux/hash.h>
+#include <linux/slab.h>
+#include "common.h"
+
+/**
+ * tomoyo_warn_oom - Print out of memory warning message.
+ *
+ * @function: Function's name.
+ */
+void tomoyo_warn_oom(const char *function)
+{
+	/* Reduce error messages. */
+	static pid_t tomoyo_last_pid;
+	const pid_t pid = current->pid;
+
+	if (tomoyo_last_pid != pid) {
+		pr_warn("ERROR: Out of memory at %s.\n", function);
+		tomoyo_last_pid = pid;
+	}
+	if (!tomoyo_policy_loaded)
+		panic("MAC Initialization failed.\n");
+}
+
+/* Memoy currently used by policy/audit log/query. */
+unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT];
+/* Memory quota for "policy"/"audit log"/"query". */
+unsigned int tomoyo_memory_quota[TOMOYO_MAX_MEMORY_STAT];
+
+/**
+ * tomoyo_memory_ok - Check memory quota.
+ *
+ * @ptr: Pointer to allocated memory.
+ *
+ * Returns true on success, false otherwise.
+ *
+ * Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
+ *
+ * Caller holds tomoyo_policy_lock mutex.
+ */
+bool tomoyo_memory_ok(void *ptr)
+{
+	if (ptr) {
+		const size_t s = ksize(ptr);
+
+		tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s;
+		if (!tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] ||
+		    tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <=
+		    tomoyo_memory_quota[TOMOYO_MEMORY_POLICY])
+			return true;
+		tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s;
+	}
+	tomoyo_warn_oom(__func__);
+	return false;
+}
+
+/**
+ * tomoyo_commit_ok - Check memory quota.
+ *
+ * @data:   Data to copy from.
+ * @size:   Size in byte.
+ *
+ * Returns pointer to allocated memory on success, NULL otherwise.
+ * @data is zero-cleared on success.
+ *
+ * Caller holds tomoyo_policy_lock mutex.
+ */
+void *tomoyo_commit_ok(void *data, const unsigned int size)
+{
+	void *ptr = kzalloc(size, GFP_NOFS | __GFP_NOWARN);
+
+	if (tomoyo_memory_ok(ptr)) {
+		memmove(ptr, data, size);
+		memset(data, 0, size);
+		return ptr;
+	}
+	kfree(ptr);
+	return NULL;
+}
+
+/**
+ * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group".
+ *
+ * @param: Pointer to "struct tomoyo_acl_param".
+ * @idx:   Index number.
+ *
+ * Returns pointer to "struct tomoyo_group" on success, NULL otherwise.
+ */
+struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param,
+				      const u8 idx)
+{
+	struct tomoyo_group e = { };
+	struct tomoyo_group *group = NULL;
+	struct list_head *list;
+	const char *group_name = tomoyo_read_token(param);
+	bool found = false;
+
+	if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP)
+		return NULL;
+	e.group_name = tomoyo_get_name(group_name);
+	if (!e.group_name)
+		return NULL;
+	if (mutex_lock_interruptible(&tomoyo_policy_lock))
+		goto out;
+	list = &param->ns->group_list[idx];
+	list_for_each_entry(group, list, head.list) {
+		if (e.group_name != group->group_name ||
+		    atomic_read(&group->head.users) == TOMOYO_GC_IN_PROGRESS)
+			continue;
+		atomic_inc(&group->head.users);
+		found = true;
+		break;
+	}
+	if (!found) {
+		struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e));
+
+		if (entry) {
+			INIT_LIST_HEAD(&entry->member_list);
+			atomic_set(&entry->head.users, 1);
+			list_add_tail_rcu(&entry->head.list, list);
+			group = entry;
+			found = true;
+		}
+	}
+	mutex_unlock(&tomoyo_policy_lock);
+out:
+	tomoyo_put_name(e.group_name);
+	return found ? group : NULL;
+}
+
+/*
+ * tomoyo_name_list is used for holding string data used by TOMOYO.
+ * Since same string data is likely used for multiple times (e.g.
+ * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
+ * "const struct tomoyo_path_info *".
+ */
+struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
+
+/**
+ * tomoyo_get_name - Allocate permanent memory for string data.
+ *
+ * @name: The string to store into the permernent memory.
+ *
+ * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
+ */
+const struct tomoyo_path_info *tomoyo_get_name(const char *name)
+{
+	struct tomoyo_name *ptr;
+	unsigned int hash;
+	int len;
+	struct list_head *head;
+
+	if (!name)
+		return NULL;
+	len = strlen(name) + 1;
+	hash = full_name_hash(NULL, (const unsigned char *) name, len - 1);
+	head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
+	if (mutex_lock_interruptible(&tomoyo_policy_lock))
+		return NULL;
+	list_for_each_entry(ptr, head, head.list) {
+		if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) ||
+		    atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS)
+			continue;
+		atomic_inc(&ptr->head.users);
+		goto out;
+	}
+	ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS | __GFP_NOWARN);
+	if (tomoyo_memory_ok(ptr)) {
+		ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
+		memmove((char *) ptr->entry.name, name, len);
+		atomic_set(&ptr->head.users, 1);
+		tomoyo_fill_path_info(&ptr->entry);
+		list_add_tail(&ptr->head.list, head);
+	} else {
+		kfree(ptr);
+		ptr = NULL;
+	}
+out:
+	mutex_unlock(&tomoyo_policy_lock);
+	return ptr ? &ptr->entry : NULL;
+}
+
+/* Initial namespace.*/
+struct tomoyo_policy_namespace tomoyo_kernel_namespace;
+
+/**
+ * tomoyo_mm_init - Initialize mm related code.
+ */
+void __init tomoyo_mm_init(void)
+{
+	int idx;
+
+	for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
+		INIT_LIST_HEAD(&tomoyo_name_list[idx]);
+	tomoyo_kernel_namespace.name = "<kernel>";
+	tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
+	tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
+	INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
+	tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
+	list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
+}