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, 432 insertions, 0 deletions

diff --git a/net/nfc/rawsock.c b/net/nfc/rawsock.c
new file mode 100644
index 000000000..f7d7a599f
--- /dev/null
+++ b/net/nfc/rawsock.c
@@ -0,0 +1,432 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2011 Instituto Nokia de Tecnologia
+ *
+ * Authors:
+ *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
+ *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
+
+#include <net/tcp_states.h>
+#include <linux/nfc.h>
+#include <linux/export.h>
+#include <linux/kcov.h>
+
+#include "nfc.h"
+
+static struct nfc_sock_list raw_sk_list = {
+	.lock = __RW_LOCK_UNLOCKED(raw_sk_list.lock)
+};
+
+static void nfc_sock_link(struct nfc_sock_list *l, struct sock *sk)
+{
+	write_lock(&l->lock);
+	sk_add_node(sk, &l->head);
+	write_unlock(&l->lock);
+}
+
+static void nfc_sock_unlink(struct nfc_sock_list *l, struct sock *sk)
+{
+	write_lock(&l->lock);
+	sk_del_node_init(sk);
+	write_unlock(&l->lock);
+}
+
+static void rawsock_write_queue_purge(struct sock *sk)
+{
+	pr_debug("sk=%p\n", sk);
+
+	spin_lock_bh(&sk->sk_write_queue.lock);
+	__skb_queue_purge(&sk->sk_write_queue);
+	nfc_rawsock(sk)->tx_work_scheduled = false;
+	spin_unlock_bh(&sk->sk_write_queue.lock);
+}
+
+static void rawsock_report_error(struct sock *sk, int err)
+{
+	pr_debug("sk=%p err=%d\n", sk, err);
+
+	sk->sk_shutdown = SHUTDOWN_MASK;
+	sk->sk_err = -err;
+	sk_error_report(sk);
+
+	rawsock_write_queue_purge(sk);
+}
+
+static int rawsock_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+
+	pr_debug("sock=%p sk=%p\n", sock, sk);
+
+	if (!sk)
+		return 0;
+
+	if (sock->type == SOCK_RAW)
+		nfc_sock_unlink(&raw_sk_list, sk);
+
+	if (sk->sk_state == TCP_ESTABLISHED) {
+		/* Prevent rawsock_tx_work from starting new transmits and
+		 * wait for any in-progress work to finish.  This must happen
+		 * before the socket is orphaned to avoid a race where
+		 * rawsock_tx_work runs after the NCI device has been freed.
+		 */
+		sk->sk_shutdown |= SEND_SHUTDOWN;
+		cancel_work_sync(&nfc_rawsock(sk)->tx_work);
+		rawsock_write_queue_purge(sk);
+	}
+
+	sock_orphan(sk);
+	sock_put(sk);
+
+	return 0;
+}
+
+static int rawsock_connect(struct socket *sock, struct sockaddr_unsized *_addr,
+			   int len, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct sockaddr_nfc *addr = (struct sockaddr_nfc *)_addr;
+	struct nfc_dev *dev;
+	int rc = 0;
+
+	pr_debug("sock=%p sk=%p flags=%d\n", sock, sk, flags);
+
+	if (!addr || len < sizeof(struct sockaddr_nfc) ||
+	    addr->sa_family != AF_NFC)
+		return -EINVAL;
+
+	pr_debug("addr dev_idx=%u target_idx=%u protocol=%u\n",
+		 addr->dev_idx, addr->target_idx, addr->nfc_protocol);
+
+	lock_sock(sk);
+
+	if (sock->state == SS_CONNECTED) {
+		rc = -EISCONN;
+		goto error;
+	}
+
+	dev = nfc_get_device(addr->dev_idx);
+	if (!dev) {
+		rc = -ENODEV;
+		goto error;
+	}
+
+	if (addr->target_idx > dev->target_next_idx - 1 ||
+	    addr->target_idx < dev->target_next_idx - dev->n_targets) {
+		rc = -EINVAL;
+		goto put_dev;
+	}
+
+	rc = nfc_activate_target(dev, addr->target_idx, addr->nfc_protocol);
+	if (rc)
+		goto put_dev;
+
+	nfc_rawsock(sk)->dev = dev;
+	nfc_rawsock(sk)->target_idx = addr->target_idx;
+	sock->state = SS_CONNECTED;
+	sk->sk_state = TCP_ESTABLISHED;
+	sk->sk_state_change(sk);
+
+	release_sock(sk);
+	return 0;
+
+put_dev:
+	nfc_put_device(dev);
+error:
+	release_sock(sk);
+	return rc;
+}
+
+static int rawsock_add_header(struct sk_buff *skb)
+{
+	*(u8 *)skb_push(skb, NFC_HEADER_SIZE) = 0;
+
+	return 0;
+}
+
+static void rawsock_data_exchange_complete(void *context, struct sk_buff *skb,
+					   int err)
+{
+	struct sock *sk = (struct sock *) context;
+
+	BUG_ON(in_hardirq());
+
+	pr_debug("sk=%p err=%d\n", sk, err);
+
+	if (err)
+		goto error;
+
+	err = rawsock_add_header(skb);
+	if (err)
+		goto error_skb;
+
+	err = sock_queue_rcv_skb(sk, skb);
+	if (err)
+		goto error_skb;
+
+	spin_lock_bh(&sk->sk_write_queue.lock);
+	if (!skb_queue_empty(&sk->sk_write_queue))
+		schedule_work(&nfc_rawsock(sk)->tx_work);
+	else
+		nfc_rawsock(sk)->tx_work_scheduled = false;
+	spin_unlock_bh(&sk->sk_write_queue.lock);
+
+	sock_put(sk);
+	return;
+
+error_skb:
+	kfree_skb(skb);
+
+error:
+	rawsock_report_error(sk, err);
+	sock_put(sk);
+}
+
+static void rawsock_tx_work(struct work_struct *work)
+{
+	struct sock *sk = to_rawsock_sk(work);
+	struct nfc_dev *dev = nfc_rawsock(sk)->dev;
+	u32 target_idx = nfc_rawsock(sk)->target_idx;
+	struct sk_buff *skb;
+	int rc;
+
+	pr_debug("sk=%p target_idx=%u\n", sk, target_idx);
+
+	if (sk->sk_shutdown & SEND_SHUTDOWN) {
+		rawsock_write_queue_purge(sk);
+		return;
+	}
+
+	skb = skb_dequeue(&sk->sk_write_queue);
+	kcov_remote_start_common(skb_get_kcov_handle(skb));
+
+	sock_hold(sk);
+	rc = nfc_data_exchange(dev, target_idx, skb,
+			       rawsock_data_exchange_complete, sk);
+	if (rc) {
+		rawsock_report_error(sk, rc);
+		sock_put(sk);
+	}
+	kcov_remote_stop();
+}
+
+static int rawsock_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
+{
+	struct sock *sk = sock->sk;
+	struct nfc_dev *dev = nfc_rawsock(sk)->dev;
+	struct sk_buff *skb;
+	int rc;
+
+	pr_debug("sock=%p sk=%p len=%zu\n", sock, sk, len);
+
+	if (msg->msg_namelen)
+		return -EOPNOTSUPP;
+
+	if (sock->state != SS_CONNECTED)
+		return -ENOTCONN;
+
+	skb = nfc_alloc_send_skb(dev, sk, msg->msg_flags, len, &rc);
+	if (skb == NULL)
+		return rc;
+
+	rc = memcpy_from_msg(skb_put(skb, len), msg, len);
+	if (rc < 0) {
+		kfree_skb(skb);
+		return rc;
+	}
+
+	spin_lock_bh(&sk->sk_write_queue.lock);
+	__skb_queue_tail(&sk->sk_write_queue, skb);
+	if (!nfc_rawsock(sk)->tx_work_scheduled) {
+		schedule_work(&nfc_rawsock(sk)->tx_work);
+		nfc_rawsock(sk)->tx_work_scheduled = true;
+	}
+	spin_unlock_bh(&sk->sk_write_queue.lock);
+
+	return len;
+}
+
+static int rawsock_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+			   int flags)
+{
+	struct sock *sk = sock->sk;
+	struct sk_buff *skb;
+	int copied;
+	int rc;
+
+	pr_debug("sock=%p sk=%p len=%zu flags=%d\n", sock, sk, len, flags);
+
+	skb = skb_recv_datagram(sk, flags, &rc);
+	if (!skb)
+		return rc;
+
+	copied = skb->len;
+	if (len < copied) {
+		msg->msg_flags |= MSG_TRUNC;
+		copied = len;
+	}
+
+	rc = skb_copy_datagram_msg(skb, 0, msg, copied);
+
+	skb_free_datagram(sk, skb);
+
+	return rc ? : copied;
+}
+
+static const struct proto_ops rawsock_ops = {
+	.family         = PF_NFC,
+	.owner          = THIS_MODULE,
+	.release        = rawsock_release,
+	.bind           = sock_no_bind,
+	.connect        = rawsock_connect,
+	.socketpair     = sock_no_socketpair,
+	.accept         = sock_no_accept,
+	.getname        = sock_no_getname,
+	.poll           = datagram_poll,
+	.ioctl          = sock_no_ioctl,
+	.listen         = sock_no_listen,
+	.shutdown       = sock_no_shutdown,
+	.sendmsg        = rawsock_sendmsg,
+	.recvmsg        = rawsock_recvmsg,
+	.mmap           = sock_no_mmap,
+};
+
+static const struct proto_ops rawsock_raw_ops = {
+	.family         = PF_NFC,
+	.owner          = THIS_MODULE,
+	.release        = rawsock_release,
+	.bind           = sock_no_bind,
+	.connect        = sock_no_connect,
+	.socketpair     = sock_no_socketpair,
+	.accept         = sock_no_accept,
+	.getname        = sock_no_getname,
+	.poll           = datagram_poll,
+	.ioctl          = sock_no_ioctl,
+	.listen         = sock_no_listen,
+	.shutdown       = sock_no_shutdown,
+	.sendmsg        = sock_no_sendmsg,
+	.recvmsg        = rawsock_recvmsg,
+	.mmap           = sock_no_mmap,
+};
+
+static void rawsock_destruct(struct sock *sk)
+{
+	pr_debug("sk=%p\n", sk);
+
+	if (sk->sk_state == TCP_ESTABLISHED) {
+		nfc_deactivate_target(nfc_rawsock(sk)->dev,
+				      nfc_rawsock(sk)->target_idx,
+				      NFC_TARGET_MODE_IDLE);
+		nfc_put_device(nfc_rawsock(sk)->dev);
+	}
+
+	skb_queue_purge(&sk->sk_receive_queue);
+
+	if (!sock_flag(sk, SOCK_DEAD)) {
+		pr_err("Freeing alive NFC raw socket %p\n", sk);
+		return;
+	}
+}
+
+static int rawsock_create(struct net *net, struct socket *sock,
+			  const struct nfc_protocol *nfc_proto, int kern)
+{
+	struct sock *sk;
+
+	pr_debug("sock=%p\n", sock);
+
+	if ((sock->type != SOCK_SEQPACKET) && (sock->type != SOCK_RAW))
+		return -ESOCKTNOSUPPORT;
+
+	if (sock->type == SOCK_RAW) {
+		if (!ns_capable(net->user_ns, CAP_NET_RAW))
+			return -EPERM;
+		sock->ops = &rawsock_raw_ops;
+	} else {
+		sock->ops = &rawsock_ops;
+	}
+
+	sk = sk_alloc(net, PF_NFC, GFP_ATOMIC, nfc_proto->proto, kern);
+	if (!sk)
+		return -ENOMEM;
+
+	sock_init_data(sock, sk);
+	sk->sk_protocol = nfc_proto->id;
+	sk->sk_destruct = rawsock_destruct;
+	sock->state = SS_UNCONNECTED;
+	if (sock->type == SOCK_RAW)
+		nfc_sock_link(&raw_sk_list, sk);
+	else {
+		INIT_WORK(&nfc_rawsock(sk)->tx_work, rawsock_tx_work);
+		nfc_rawsock(sk)->tx_work_scheduled = false;
+	}
+
+	return 0;
+}
+
+void nfc_send_to_raw_sock(struct nfc_dev *dev, struct sk_buff *skb,
+			  u8 payload_type, u8 direction)
+{
+	struct sk_buff *skb_copy = NULL, *nskb;
+	struct sock *sk;
+	u8 *data;
+
+	read_lock(&raw_sk_list.lock);
+
+	sk_for_each(sk, &raw_sk_list.head) {
+		if (!skb_copy) {
+			skb_copy = __pskb_copy_fclone(skb, NFC_RAW_HEADER_SIZE,
+						      GFP_ATOMIC, true);
+			if (!skb_copy)
+				continue;
+
+			data = skb_push(skb_copy, NFC_RAW_HEADER_SIZE);
+
+			data[0] = dev ? dev->idx : 0xFF;
+			data[1] = direction & 0x01;
+			data[1] |= (payload_type << 1);
+		}
+
+		nskb = skb_clone(skb_copy, GFP_ATOMIC);
+		if (!nskb)
+			continue;
+
+		if (sock_queue_rcv_skb(sk, nskb))
+			kfree_skb(nskb);
+	}
+
+	read_unlock(&raw_sk_list.lock);
+
+	kfree_skb(skb_copy);
+}
+EXPORT_SYMBOL(nfc_send_to_raw_sock);
+
+static struct proto rawsock_proto = {
+	.name     = "NFC_RAW",
+	.owner    = THIS_MODULE,
+	.obj_size = sizeof(struct nfc_rawsock),
+};
+
+static const struct nfc_protocol rawsock_nfc_proto = {
+	.id	  = NFC_SOCKPROTO_RAW,
+	.proto    = &rawsock_proto,
+	.owner    = THIS_MODULE,
+	.create   = rawsock_create
+};
+
+int __init rawsock_init(void)
+{
+	int rc;
+
+	rc = nfc_proto_register(&rawsock_nfc_proto);
+
+	return rc;
+}
+
+void rawsock_exit(void)
+{
+	nfc_proto_unregister(&rawsock_nfc_proto);
+}