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, 257 insertions, 0 deletions

diff --git a/net/bluetooth/bnep/sock.c b/net/bluetooth/bnep/sock.c
new file mode 100644
index 000000000..f3fe818d0
--- /dev/null
+++ b/net/bluetooth/bnep/sock.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+   BNEP implementation for Linux Bluetooth stack (BlueZ).
+   Copyright (C) 2001-2002 Inventel Systemes
+   Written 2001-2002 by
+	David Libault  <david.libault@inventel.fr>
+
+   Copyright (C) 2002 Maxim Krasnyansky <maxk@qualcomm.com>
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
+   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
+   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
+   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
+   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
+   SOFTWARE IS DISCLAIMED.
+*/
+
+#include <linux/compat.h>
+#include <linux/export.h>
+#include <linux/file.h>
+
+#include "bnep.h"
+
+static struct bt_sock_list bnep_sk_list = {
+	.lock = __RW_LOCK_UNLOCKED(bnep_sk_list.lock)
+};
+
+static int bnep_sock_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+
+	BT_DBG("sock %p sk %p", sock, sk);
+
+	if (!sk)
+		return 0;
+
+	bt_sock_unlink(&bnep_sk_list, sk);
+
+	sock_orphan(sk);
+	sock_put(sk);
+	return 0;
+}
+
+static int do_bnep_sock_ioctl(struct socket *sock, unsigned int cmd, void __user *argp)
+{
+	struct bnep_connlist_req cl;
+	struct bnep_connadd_req  ca;
+	struct bnep_conndel_req  cd;
+	struct bnep_conninfo ci;
+	struct socket *nsock;
+	__u32 supp_feat = BIT(BNEP_SETUP_RESPONSE);
+	int err;
+
+	BT_DBG("cmd %x arg %p", cmd, argp);
+
+	switch (cmd) {
+	case BNEPCONNADD:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		if (copy_from_user(&ca, argp, sizeof(ca)))
+			return -EFAULT;
+
+		nsock = sockfd_lookup(ca.sock, &err);
+		if (!nsock)
+			return err;
+
+		if (nsock->sk->sk_state != BT_CONNECTED) {
+			sockfd_put(nsock);
+			return -EBADFD;
+		}
+		ca.device[sizeof(ca.device)-1] = 0;
+
+		err = bnep_add_connection(&ca, nsock);
+		if (!err) {
+			if (copy_to_user(argp, &ca, sizeof(ca)))
+				err = -EFAULT;
+		} else
+			sockfd_put(nsock);
+
+		return err;
+
+	case BNEPCONNDEL:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		if (copy_from_user(&cd, argp, sizeof(cd)))
+			return -EFAULT;
+
+		return bnep_del_connection(&cd);
+
+	case BNEPGETCONNLIST:
+		if (copy_from_user(&cl, argp, sizeof(cl)))
+			return -EFAULT;
+
+		if (cl.cnum <= 0)
+			return -EINVAL;
+
+		err = bnep_get_connlist(&cl);
+		if (!err && copy_to_user(argp, &cl, sizeof(cl)))
+			return -EFAULT;
+
+		return err;
+
+	case BNEPGETCONNINFO:
+		if (copy_from_user(&ci, argp, sizeof(ci)))
+			return -EFAULT;
+
+		err = bnep_get_conninfo(&ci);
+		if (!err && copy_to_user(argp, &ci, sizeof(ci)))
+			return -EFAULT;
+
+		return err;
+
+	case BNEPGETSUPPFEAT:
+		if (copy_to_user(argp, &supp_feat, sizeof(supp_feat)))
+			return -EFAULT;
+
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int bnep_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	return do_bnep_sock_ioctl(sock, cmd, (void __user *)arg);
+}
+
+#ifdef CONFIG_COMPAT
+static int bnep_sock_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = compat_ptr(arg);
+	if (cmd == BNEPGETCONNLIST) {
+		struct bnep_connlist_req cl;
+		unsigned __user *p = argp;
+		u32 uci;
+		int err;
+
+		if (get_user(cl.cnum, p) || get_user(uci, p + 1))
+			return -EFAULT;
+
+		cl.ci = compat_ptr(uci);
+
+		if (cl.cnum <= 0)
+			return -EINVAL;
+
+		err = bnep_get_connlist(&cl);
+
+		if (!err && put_user(cl.cnum, p))
+			err = -EFAULT;
+
+		return err;
+	}
+
+	return do_bnep_sock_ioctl(sock, cmd, argp);
+}
+#endif
+
+static const struct proto_ops bnep_sock_ops = {
+	.family		= PF_BLUETOOTH,
+	.owner		= THIS_MODULE,
+	.release	= bnep_sock_release,
+	.ioctl		= bnep_sock_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= bnep_sock_compat_ioctl,
+#endif
+	.bind		= sock_no_bind,
+	.getname	= sock_no_getname,
+	.sendmsg	= sock_no_sendmsg,
+	.recvmsg	= sock_no_recvmsg,
+	.listen		= sock_no_listen,
+	.shutdown	= sock_no_shutdown,
+	.connect	= sock_no_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= sock_no_accept,
+	.mmap		= sock_no_mmap
+};
+
+static struct proto bnep_proto = {
+	.name		= "BNEP",
+	.owner		= THIS_MODULE,
+	.obj_size	= sizeof(struct bt_sock)
+};
+
+static int bnep_sock_create(struct net *net, struct socket *sock, int protocol,
+			    int kern)
+{
+	struct sock *sk;
+
+	BT_DBG("sock %p", sock);
+
+	if (sock->type != SOCK_RAW)
+		return -ESOCKTNOSUPPORT;
+
+	sk = bt_sock_alloc(net, sock, &bnep_proto, protocol, GFP_ATOMIC, kern);
+	if (!sk)
+		return -ENOMEM;
+
+	sock->ops = &bnep_sock_ops;
+	sock->state = SS_UNCONNECTED;
+
+	bt_sock_link(&bnep_sk_list, sk);
+	return 0;
+}
+
+static const struct net_proto_family bnep_sock_family_ops = {
+	.family = PF_BLUETOOTH,
+	.owner	= THIS_MODULE,
+	.create = bnep_sock_create
+};
+
+int __init bnep_sock_init(void)
+{
+	int err;
+
+	err = proto_register(&bnep_proto, 0);
+	if (err < 0)
+		return err;
+
+	err = bt_sock_register(BTPROTO_BNEP, &bnep_sock_family_ops);
+	if (err < 0) {
+		BT_ERR("Can't register BNEP socket");
+		goto error;
+	}
+
+	err = bt_procfs_init(&init_net, "bnep", &bnep_sk_list, NULL);
+	if (err < 0) {
+		BT_ERR("Failed to create BNEP proc file");
+		bt_sock_unregister(BTPROTO_BNEP);
+		goto error;
+	}
+
+	BT_INFO("BNEP socket layer initialized");
+
+	return 0;
+
+error:
+	proto_unregister(&bnep_proto);
+	return err;
+}
+
+void __exit bnep_sock_cleanup(void)
+{
+	bt_procfs_cleanup(&init_net, "bnep");
+	bt_sock_unregister(BTPROTO_BNEP);
+	proto_unregister(&bnep_proto);
+}