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, 725 insertions, 0 deletions

diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
new file mode 100644
index 000000000..c7e7e924f
--- /dev/null
+++ b/net/bridge/br_stp.c
@@ -0,0 +1,725 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Spanning tree protocol; generic parts
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ */
+#include <linux/kernel.h>
+#include <linux/rculist.h>
+#include <net/switchdev.h>
+
+#include "br_private.h"
+#include "br_private_stp.h"
+
+/* since time values in bpdu are in jiffies and then scaled (1/256)
+ * before sending, make sure that is at least one STP tick.
+ */
+#define MESSAGE_AGE_INCR	((HZ / 256) + 1)
+
+static const char *const br_port_state_names[] = {
+	[BR_STATE_DISABLED] = "disabled",
+	[BR_STATE_LISTENING] = "listening",
+	[BR_STATE_LEARNING] = "learning",
+	[BR_STATE_FORWARDING] = "forwarding",
+	[BR_STATE_BLOCKING] = "blocking",
+};
+
+void br_set_state(struct net_bridge_port *p, unsigned int state)
+{
+	struct switchdev_attr attr = {
+		.orig_dev = p->dev,
+		.id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
+		.flags = SWITCHDEV_F_DEFER,
+		.u.stp_state = state,
+	};
+	int err;
+
+	/* Don't change the state of the ports if they are driven by a different
+	 * protocol.
+	 */
+	if (test_bit(BR_MRP_AWARE_BIT, &p->flags))
+		return;
+
+	p->state = state;
+	if (br_opt_get(p->br, BROPT_MST_ENABLED)) {
+		err = br_mst_set_state(p, 0, state, NULL);
+		if (err)
+			br_warn(p->br, "error setting MST state on port %u(%s)\n",
+				p->port_no, netdev_name(p->dev));
+	}
+	err = switchdev_port_attr_set(p->dev, &attr, NULL);
+	if (err && err != -EOPNOTSUPP)
+		br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
+				(unsigned int) p->port_no, p->dev->name);
+	else
+		br_info(p->br, "port %u(%s) entered %s state\n",
+				(unsigned int) p->port_no, p->dev->name,
+				br_port_state_names[p->state]);
+
+	if (p->br->stp_enabled == BR_KERNEL_STP) {
+		switch (p->state) {
+		case BR_STATE_BLOCKING:
+			p->stp_xstats.transition_blk++;
+			break;
+		case BR_STATE_FORWARDING:
+			p->stp_xstats.transition_fwd++;
+			break;
+		}
+	}
+}
+
+u8 br_port_get_stp_state(const struct net_device *dev)
+{
+	struct net_bridge_port *p;
+
+	ASSERT_RTNL();
+
+	p = br_port_get_rtnl(dev);
+	if (!p)
+		return BR_STATE_DISABLED;
+
+	return p->state;
+}
+EXPORT_SYMBOL_GPL(br_port_get_stp_state);
+
+/* called under bridge lock */
+struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
+{
+	struct net_bridge_port *p;
+
+	list_for_each_entry_rcu(p, &br->port_list, list,
+				lockdep_is_held(&br->lock)) {
+		if (p->port_no == port_no)
+			return p;
+	}
+
+	return NULL;
+}
+
+/* called under bridge lock */
+static int br_should_become_root_port(const struct net_bridge_port *p,
+				      u16 root_port)
+{
+	u32 p_path_cost, rp_path_cost, p_designated_cost, rp_designated_cost;
+	struct net_bridge_port *rp;
+	struct net_bridge *br;
+	int t;
+
+	br = p->br;
+	if (p->state == BR_STATE_DISABLED ||
+	    br_is_designated_port(p))
+		return 0;
+
+	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
+		return 0;
+
+	if (!root_port)
+		return 1;
+
+	rp = br_get_port(br, root_port);
+
+	t = memcmp(&p->designated_root, &rp->designated_root, 8);
+	if (t < 0)
+		return 1;
+	else if (t > 0)
+		return 0;
+
+	p_path_cost = READ_ONCE(p->path_cost);
+	rp_path_cost = READ_ONCE(rp->path_cost);
+	p_designated_cost = READ_ONCE(p->designated_cost);
+	rp_designated_cost = READ_ONCE(rp->designated_cost);
+
+	if (p_designated_cost + p_path_cost <
+	    rp_designated_cost + rp_path_cost)
+		return 1;
+	else if (p_designated_cost + p_path_cost >
+		 rp_designated_cost + rp_path_cost)
+		return 0;
+
+	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
+	if (t < 0)
+		return 1;
+	else if (t > 0)
+		return 0;
+
+	if (p->designated_port < rp->designated_port)
+		return 1;
+	else if (p->designated_port > rp->designated_port)
+		return 0;
+
+	if (p->port_id < rp->port_id)
+		return 1;
+
+	return 0;
+}
+
+static void br_root_port_block(const struct net_bridge *br,
+			       struct net_bridge_port *p)
+{
+
+	br_notice(br, "port %u(%s) tried to become root port (blocked)",
+		  (unsigned int) p->port_no, p->dev->name);
+
+	br_set_state(p, BR_STATE_LISTENING);
+	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
+
+	if (br->forward_delay > 0)
+		mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
+}
+
+/* called under bridge lock */
+static void br_root_selection(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+	u16 root_port = 0;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (!br_should_become_root_port(p, root_port))
+			continue;
+
+		if (test_bit(BR_ROOT_BLOCK_BIT, &p->flags))
+			br_root_port_block(br, p);
+		else
+			root_port = p->port_no;
+	}
+
+	br->root_port = root_port;
+
+	if (!root_port) {
+		br->designated_root = br->bridge_id;
+		br->root_path_cost = 0;
+	} else {
+		p = br_get_port(br, root_port);
+		br->designated_root = p->designated_root;
+		br->root_path_cost = READ_ONCE(p->designated_cost) +
+				     READ_ONCE(p->path_cost);
+	}
+}
+
+/* called under bridge lock */
+void br_become_root_bridge(struct net_bridge *br)
+{
+	br->max_age = br->bridge_max_age;
+	br->hello_time = br->bridge_hello_time;
+	br->forward_delay = br->bridge_forward_delay;
+	br_topology_change_detection(br);
+	timer_delete(&br->tcn_timer);
+
+	if (br->dev->flags & IFF_UP) {
+		br_config_bpdu_generation(br);
+		mod_timer(&br->hello_timer, jiffies + br->hello_time);
+	}
+}
+
+/* called under bridge lock */
+void br_transmit_config(struct net_bridge_port *p)
+{
+	struct br_config_bpdu bpdu;
+	struct net_bridge *br;
+
+	if (timer_pending(&p->hold_timer)) {
+		WRITE_ONCE(p->config_pending, 1);
+		return;
+	}
+
+	br = p->br;
+
+	bpdu.topology_change = br->topology_change;
+	bpdu.topology_change_ack = p->topology_change_ack;
+	bpdu.root = br->designated_root;
+	bpdu.root_path_cost = br->root_path_cost;
+	bpdu.bridge_id = br->bridge_id;
+	bpdu.port_id = p->port_id;
+	if (br_is_root_bridge(br))
+		bpdu.message_age = 0;
+	else {
+		struct net_bridge_port *root
+			= br_get_port(br, br->root_port);
+		bpdu.message_age = (jiffies - root->designated_age)
+			+ MESSAGE_AGE_INCR;
+	}
+	bpdu.max_age = br->max_age;
+	bpdu.hello_time = br->hello_time;
+	bpdu.forward_delay = br->forward_delay;
+
+	if (bpdu.message_age < br->max_age) {
+		br_send_config_bpdu(p, &bpdu);
+		p->topology_change_ack = 0;
+		WRITE_ONCE(p->config_pending, 0);
+		if (p->br->stp_enabled == BR_KERNEL_STP)
+			mod_timer(&p->hold_timer,
+				  round_jiffies(jiffies + BR_HOLD_TIME));
+	}
+}
+
+/* called under bridge lock */
+static void br_record_config_information(struct net_bridge_port *p,
+					 const struct br_config_bpdu *bpdu)
+{
+	p->designated_root = bpdu->root;
+	WRITE_ONCE(p->designated_cost, bpdu->root_path_cost);
+	p->designated_bridge = bpdu->bridge_id;
+	WRITE_ONCE(p->designated_port, bpdu->port_id);
+	p->designated_age = jiffies - bpdu->message_age;
+
+	mod_timer(&p->message_age_timer, jiffies
+		  + (bpdu->max_age - bpdu->message_age));
+}
+
+/* called under bridge lock */
+static void br_record_config_timeout_values(struct net_bridge *br,
+					    const struct br_config_bpdu *bpdu)
+{
+	br->max_age = bpdu->max_age;
+	br->hello_time = bpdu->hello_time;
+	br->forward_delay = bpdu->forward_delay;
+	__br_set_topology_change(br, bpdu->topology_change);
+}
+
+/* called under bridge lock */
+void br_transmit_tcn(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+
+	p = br_get_port(br, br->root_port);
+	if (p)
+		br_send_tcn_bpdu(p);
+	else
+		br_notice(br, "root port %u not found for topology notice\n",
+			  br->root_port);
+}
+
+/* called under bridge lock */
+static int br_should_become_designated_port(const struct net_bridge_port *p)
+{
+	struct net_bridge *br;
+	u32 p_designated_cost;
+	int t;
+
+	br = p->br;
+	if (br_is_designated_port(p))
+		return 1;
+
+	if (memcmp(&p->designated_root, &br->designated_root, 8))
+		return 1;
+
+	p_designated_cost = READ_ONCE(p->designated_cost);
+	if (br->root_path_cost < p_designated_cost)
+		return 1;
+	else if (br->root_path_cost > p_designated_cost)
+		return 0;
+
+	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
+	if (t < 0)
+		return 1;
+	else if (t > 0)
+		return 0;
+
+	if (p->port_id < p->designated_port)
+		return 1;
+
+	return 0;
+}
+
+/* called under bridge lock */
+static void br_designated_port_selection(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (p->state != BR_STATE_DISABLED &&
+		    br_should_become_designated_port(p))
+			br_become_designated_port(p);
+
+	}
+}
+
+/* called under bridge lock */
+static int br_supersedes_port_info(const struct net_bridge_port *p,
+				   const struct br_config_bpdu *bpdu)
+{
+	u32 p_designated_cost;
+	int t;
+
+	t = memcmp(&bpdu->root, &p->designated_root, 8);
+	if (t < 0)
+		return 1;
+	else if (t > 0)
+		return 0;
+
+	p_designated_cost = READ_ONCE(p->designated_cost);
+	if (bpdu->root_path_cost < p_designated_cost)
+		return 1;
+	else if (bpdu->root_path_cost > p_designated_cost)
+		return 0;
+
+	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
+	if (t < 0)
+		return 1;
+	else if (t > 0)
+		return 0;
+
+	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
+		return 1;
+
+	if (bpdu->port_id <= p->designated_port)
+		return 1;
+
+	return 0;
+}
+
+/* called under bridge lock */
+static void br_topology_change_acknowledged(struct net_bridge *br)
+{
+	br->topology_change_detected = 0;
+	timer_delete(&br->tcn_timer);
+}
+
+/* called under bridge lock */
+void br_topology_change_detection(struct net_bridge *br)
+{
+	int isroot = br_is_root_bridge(br);
+
+	if (br->stp_enabled != BR_KERNEL_STP ||
+	    !(br->dev->flags & IFF_UP))
+		return;
+
+	br_info(br, "topology change detected, %s\n",
+		isroot ? "propagating" : "sending tcn bpdu");
+
+	if (isroot) {
+		__br_set_topology_change(br, 1);
+		mod_timer(&br->topology_change_timer, jiffies
+			  + br->bridge_forward_delay + br->bridge_max_age);
+	} else if (!br->topology_change_detected) {
+		br_transmit_tcn(br);
+		mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
+	}
+
+	br->topology_change_detected = 1;
+}
+
+/* called under bridge lock */
+void br_config_bpdu_generation(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (p->state != BR_STATE_DISABLED &&
+		    br_is_designated_port(p))
+			br_transmit_config(p);
+	}
+}
+
+/* called under bridge lock */
+static void br_reply(struct net_bridge_port *p)
+{
+	br_transmit_config(p);
+}
+
+/* called under bridge lock */
+void br_configuration_update(struct net_bridge *br)
+{
+	br_root_selection(br);
+	br_designated_port_selection(br);
+}
+
+/* called under bridge lock */
+void br_become_designated_port(struct net_bridge_port *p)
+{
+	struct net_bridge *br;
+
+	br = p->br;
+	p->designated_root = br->designated_root;
+	WRITE_ONCE(p->designated_cost, br->root_path_cost);
+	p->designated_bridge = br->bridge_id;
+	WRITE_ONCE(p->designated_port, p->port_id);
+}
+
+
+/* called under bridge lock */
+static void br_make_blocking(struct net_bridge_port *p)
+{
+	if (p->state != BR_STATE_DISABLED &&
+	    p->state != BR_STATE_BLOCKING) {
+		if (p->state == BR_STATE_FORWARDING ||
+		    p->state == BR_STATE_LEARNING)
+			br_topology_change_detection(p->br);
+
+		br_set_state(p, BR_STATE_BLOCKING);
+		br_ifinfo_notify(RTM_NEWLINK, NULL, p);
+
+		timer_delete(&p->forward_delay_timer);
+	}
+}
+
+/* called under bridge lock */
+static void br_make_forwarding(struct net_bridge_port *p)
+{
+	struct net_bridge *br = p->br;
+
+	if (p->state != BR_STATE_BLOCKING)
+		return;
+
+	if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
+		br_set_state(p, BR_STATE_FORWARDING);
+		br_topology_change_detection(br);
+		timer_delete(&p->forward_delay_timer);
+	} else if (br->stp_enabled == BR_KERNEL_STP)
+		br_set_state(p, BR_STATE_LISTENING);
+	else
+		br_set_state(p, BR_STATE_LEARNING);
+
+	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
+
+	if (br->forward_delay != 0)
+		mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
+}
+
+/* called under bridge lock */
+void br_port_state_selection(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+	unsigned int liveports = 0;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (p->state == BR_STATE_DISABLED)
+			continue;
+
+		/* Don't change port states if userspace is handling STP */
+		if (br->stp_enabled != BR_USER_STP) {
+			if (p->port_no == br->root_port) {
+				WRITE_ONCE(p->config_pending, 0);
+				p->topology_change_ack = 0;
+				br_make_forwarding(p);
+			} else if (br_is_designated_port(p)) {
+				timer_delete(&p->message_age_timer);
+				br_make_forwarding(p);
+			} else {
+				WRITE_ONCE(p->config_pending, 0);
+				p->topology_change_ack = 0;
+				br_make_blocking(p);
+			}
+		}
+
+		if (p->state != BR_STATE_BLOCKING)
+			br_multicast_enable_port(p);
+		/* Multicast is not disabled for the port when it goes in
+		 * blocking state because the timers will expire and stop by
+		 * themselves without sending more queries.
+		 */
+		if (p->state == BR_STATE_FORWARDING)
+			++liveports;
+	}
+
+	if (liveports == 0)
+		netif_carrier_off(br->dev);
+	else
+		netif_carrier_on(br->dev);
+}
+
+/* called under bridge lock */
+static void br_topology_change_acknowledge(struct net_bridge_port *p)
+{
+	p->topology_change_ack = 1;
+	br_transmit_config(p);
+}
+
+/* called under bridge lock */
+void br_received_config_bpdu(struct net_bridge_port *p,
+			     const struct br_config_bpdu *bpdu)
+{
+	struct net_bridge *br;
+	int was_root;
+
+	p->stp_xstats.rx_bpdu++;
+
+	br = p->br;
+	was_root = br_is_root_bridge(br);
+
+	if (br_supersedes_port_info(p, bpdu)) {
+		br_record_config_information(p, bpdu);
+		br_configuration_update(br);
+		br_port_state_selection(br);
+
+		if (!br_is_root_bridge(br) && was_root) {
+			timer_delete(&br->hello_timer);
+			if (br->topology_change_detected) {
+				timer_delete(&br->topology_change_timer);
+				br_transmit_tcn(br);
+
+				mod_timer(&br->tcn_timer,
+					  jiffies + br->bridge_hello_time);
+			}
+		}
+
+		if (p->port_no == br->root_port) {
+			br_record_config_timeout_values(br, bpdu);
+			br_config_bpdu_generation(br);
+			if (bpdu->topology_change_ack)
+				br_topology_change_acknowledged(br);
+		}
+	} else if (br_is_designated_port(p)) {
+		br_reply(p);
+	}
+}
+
+/* called under bridge lock */
+void br_received_tcn_bpdu(struct net_bridge_port *p)
+{
+	p->stp_xstats.rx_tcn++;
+
+	if (br_is_designated_port(p)) {
+		br_info(p->br, "port %u(%s) received tcn bpdu\n",
+			(unsigned int) p->port_no, p->dev->name);
+
+		br_topology_change_detection(p->br);
+		br_topology_change_acknowledge(p);
+	}
+}
+
+/* Change bridge STP parameter */
+int br_set_hello_time(struct net_bridge *br, unsigned long val)
+{
+	unsigned long t = clock_t_to_jiffies(val);
+
+	if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
+		return -ERANGE;
+
+	spin_lock_bh(&br->lock);
+	br->bridge_hello_time = t;
+	if (br_is_root_bridge(br))
+		br->hello_time = br->bridge_hello_time;
+	spin_unlock_bh(&br->lock);
+	return 0;
+}
+
+int br_set_max_age(struct net_bridge *br, unsigned long val)
+{
+	unsigned long t = clock_t_to_jiffies(val);
+
+	if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
+		return -ERANGE;
+
+	spin_lock_bh(&br->lock);
+	br->bridge_max_age = t;
+	if (br_is_root_bridge(br))
+		br->max_age = br->bridge_max_age;
+	spin_unlock_bh(&br->lock);
+	return 0;
+
+}
+
+/* called under bridge lock */
+int __set_ageing_time(struct net_device *dev, unsigned long t)
+{
+	struct switchdev_attr attr = {
+		.orig_dev = dev,
+		.id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
+		.flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER,
+		.u.ageing_time = jiffies_to_clock_t(t),
+	};
+	int err;
+
+	err = switchdev_port_attr_set(dev, &attr, NULL);
+	if (err && err != -EOPNOTSUPP)
+		return err;
+
+	return 0;
+}
+
+/* Set time interval that dynamic forwarding entries live
+ * For pure software bridge, allow values outside the 802.1
+ * standard specification for special cases:
+ *  0 - entry never ages (all permanent)
+ *  1 - entry disappears (no persistence)
+ *
+ * Offloaded switch entries maybe more restrictive
+ */
+int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time)
+{
+	unsigned long t = clock_t_to_jiffies(ageing_time);
+	int err;
+
+	err = __set_ageing_time(br->dev, t);
+	if (err)
+		return err;
+
+	spin_lock_bh(&br->lock);
+	br->bridge_ageing_time = t;
+	br->ageing_time = t;
+	spin_unlock_bh(&br->lock);
+
+	mod_delayed_work(system_long_wq, &br->gc_work, 0);
+
+	return 0;
+}
+
+clock_t br_get_ageing_time(const struct net_device *br_dev)
+{
+	const struct net_bridge *br;
+
+	if (!netif_is_bridge_master(br_dev))
+		return 0;
+
+	br = netdev_priv(br_dev);
+
+	return jiffies_to_clock_t(br->ageing_time);
+}
+EXPORT_SYMBOL_GPL(br_get_ageing_time);
+
+/* called under bridge lock */
+void __br_set_topology_change(struct net_bridge *br, unsigned char val)
+{
+	unsigned long t;
+	int err;
+
+	if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) {
+		/* On topology change, set the bridge ageing time to twice the
+		 * forward delay. Otherwise, restore its default ageing time.
+		 */
+
+		if (val) {
+			t = 2 * br->forward_delay;
+			br_debug(br, "decreasing ageing time to %lu\n", t);
+		} else {
+			t = br->bridge_ageing_time;
+			br_debug(br, "restoring ageing time to %lu\n", t);
+		}
+
+		err = __set_ageing_time(br->dev, t);
+		if (err)
+			br_warn(br, "error offloading ageing time\n");
+		else
+			br->ageing_time = t;
+	}
+
+	br->topology_change = val;
+}
+
+void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
+{
+	br->bridge_forward_delay = t;
+	if (br_is_root_bridge(br))
+		br->forward_delay = br->bridge_forward_delay;
+}
+
+int br_set_forward_delay(struct net_bridge *br, unsigned long val)
+{
+	unsigned long t = clock_t_to_jiffies(val);
+	int err = -ERANGE;
+
+	spin_lock_bh(&br->lock);
+	if (br->stp_enabled != BR_NO_STP &&
+	    (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
+		goto unlock;
+
+	__br_set_forward_delay(br, t);
+	err = 0;
+
+unlock:
+	spin_unlock_bh(&br->lock);
+	return err;
+}