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, 124 insertions, 0 deletions

diff --git a/security/tomoyo/environ.c b/security/tomoyo/environ.c
new file mode 100644
index 000000000..bcb05910f
--- /dev/null
+++ b/security/tomoyo/environ.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * security/tomoyo/environ.c
+ *
+ * Copyright (C) 2005-2011  NTT DATA CORPORATION
+ */
+
+#include "common.h"
+
+/**
+ * tomoyo_check_env_acl - Check permission for environment variable's name.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @ptr: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if granted, false otherwise.
+ */
+static bool tomoyo_check_env_acl(struct tomoyo_request_info *r,
+				 const struct tomoyo_acl_info *ptr)
+{
+	const struct tomoyo_env_acl *acl =
+		container_of(ptr, typeof(*acl), head);
+
+	return tomoyo_path_matches_pattern(r->param.environ.name, acl->env);
+}
+
+/**
+ * tomoyo_audit_env_log - Audit environment variable name log.
+ *
+ * @r: Pointer to "struct tomoyo_request_info".
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_audit_env_log(struct tomoyo_request_info *r)
+	__must_hold_shared(&tomoyo_ss)
+{
+	return tomoyo_supervisor(r, "misc env %s\n",
+				 r->param.environ.name->name);
+}
+
+/**
+ * tomoyo_env_perm - Check permission for environment variable's name.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @env: The name of environment variable.
+ *
+ * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+int tomoyo_env_perm(struct tomoyo_request_info *r, const char *env)
+{
+	struct tomoyo_path_info environ;
+	int error;
+
+	if (!env || !*env)
+		return 0;
+	environ.name = env;
+	tomoyo_fill_path_info(&environ);
+	r->param_type = TOMOYO_TYPE_ENV_ACL;
+	r->param.environ.name = &environ;
+	do {
+		tomoyo_check_acl(r, tomoyo_check_env_acl);
+		error = tomoyo_audit_env_log(r);
+	} while (error == TOMOYO_RETRY_REQUEST);
+	return error;
+}
+
+/**
+ * tomoyo_same_env_acl - Check for duplicated "struct tomoyo_env_acl" entry.
+ *
+ * @a: Pointer to "struct tomoyo_acl_info".
+ * @b: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if @a == @b, false otherwise.
+ */
+static bool tomoyo_same_env_acl(const struct tomoyo_acl_info *a,
+				const struct tomoyo_acl_info *b)
+{
+	const struct tomoyo_env_acl *p1 = container_of(a, typeof(*p1), head);
+	const struct tomoyo_env_acl *p2 = container_of(b, typeof(*p2), head);
+
+	return p1->env == p2->env;
+}
+
+/**
+ * tomoyo_write_env - Write "struct tomoyo_env_acl" list.
+ *
+ * @param: Pointer to "struct tomoyo_acl_param".
+ *
+ * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+static int tomoyo_write_env(struct tomoyo_acl_param *param)
+{
+	struct tomoyo_env_acl e = { .head.type = TOMOYO_TYPE_ENV_ACL };
+	int error = -ENOMEM;
+	const char *data = tomoyo_read_token(param);
+
+	if (!tomoyo_correct_word(data) || strchr(data, '='))
+		return -EINVAL;
+	e.env = tomoyo_get_name(data);
+	if (!e.env)
+		return error;
+	error = tomoyo_update_domain(&e.head, sizeof(e), param,
+				  tomoyo_same_env_acl, NULL);
+	tomoyo_put_name(e.env);
+	return error;
+}
+
+/**
+ * tomoyo_write_misc - Update environment variable list.
+ *
+ * @param: Pointer to "struct tomoyo_acl_param".
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_write_misc(struct tomoyo_acl_param *param)
+{
+	if (tomoyo_str_starts(&param->data, "env "))
+		return tomoyo_write_env(param);
+	return -EINVAL;
+}