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, 248 insertions, 0 deletions

diff --git a/net/mac80211/ocb.c b/net/mac80211/ocb.c
new file mode 100644
index 000000000..e9bf4ba3e
--- /dev/null
+++ b/net/mac80211/ocb.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OCB mode implementation
+ *
+ * Copyright: (c) 2014 Czech Technical University in Prague
+ *            (c) 2014 Volkswagen Group Research
+ * Copyright (C) 2022 - 2024, 2026 Intel Corporation
+ * Author:    Rostislav Lisovy <rostislav.lisovy@fel.cvut.cz>
+ * Funded by: Volkswagen Group Research
+ */
+
+#include <linux/delay.h>
+#include <linux/if_ether.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <linux/etherdevice.h>
+#include <linux/rtnetlink.h>
+#include <net/mac80211.h>
+#include <linux/unaligned.h>
+
+#include "ieee80211_i.h"
+#include "driver-ops.h"
+#include "rate.h"
+
+#define IEEE80211_OCB_HOUSEKEEPING_INTERVAL		(60 * HZ)
+#define IEEE80211_OCB_PEER_INACTIVITY_LIMIT		(240 * HZ)
+#define IEEE80211_OCB_MAX_STA_ENTRIES			128
+
+/**
+ * enum ocb_deferred_task_flags - mac80211 OCB deferred tasks
+ * @OCB_WORK_HOUSEKEEPING: run the periodic OCB housekeeping tasks
+ *
+ * These flags are used in @wrkq_flags field of &struct ieee80211_if_ocb
+ */
+enum ocb_deferred_task_flags {
+	OCB_WORK_HOUSEKEEPING,
+};
+
+void ieee80211_ocb_rx_no_sta(struct ieee80211_sub_if_data *sdata,
+			     const u8 *bssid, const u8 *addr,
+			     u32 supp_rates)
+{
+	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx_conf *chanctx_conf;
+	struct ieee80211_supported_band *sband;
+	struct sta_info *sta;
+	int band;
+
+	if (!ifocb->joined)
+		return;
+
+	/* XXX: Consider removing the least recently used entry and
+	 *      allow new one to be added.
+	 */
+	if (local->num_sta >= IEEE80211_OCB_MAX_STA_ENTRIES) {
+		net_info_ratelimited("%s: No room for a new OCB STA entry %pM\n",
+				     sdata->name, addr);
+		return;
+	}
+
+	ocb_dbg(sdata, "Adding new OCB station %pM\n", addr);
+
+	rcu_read_lock();
+	chanctx_conf = rcu_dereference(sdata->vif.bss_conf.chanctx_conf);
+	if (WARN_ON_ONCE(!chanctx_conf)) {
+		rcu_read_unlock();
+		return;
+	}
+	band = chanctx_conf->def.chan->band;
+	rcu_read_unlock();
+
+	sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
+	if (!sta)
+		return;
+
+	/* Add only mandatory rates for now */
+	sband = local->hw.wiphy->bands[band];
+	sta->sta.deflink.supp_rates[band] = ieee80211_mandatory_rates(sband);
+
+	spin_lock(&ifocb->incomplete_lock);
+	list_add(&sta->list, &ifocb->incomplete_stations);
+	spin_unlock(&ifocb->incomplete_lock);
+	wiphy_work_queue(local->hw.wiphy, &sdata->work);
+}
+
+static struct sta_info *ieee80211_ocb_finish_sta(struct sta_info *sta)
+	__acquires(RCU)
+{
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
+	u8 addr[ETH_ALEN];
+
+	memcpy(addr, sta->sta.addr, ETH_ALEN);
+
+	ieee80211_sta_init_nss_bw_capa(&sta->deflink,
+				       &sdata->deflink.conf->chanreq.oper);
+
+	ocb_dbg(sdata, "Adding new IBSS station %pM (dev=%s)\n",
+		addr, sdata->name);
+
+	sta_info_move_state(sta, IEEE80211_STA_AUTH);
+	sta_info_move_state(sta, IEEE80211_STA_ASSOC);
+	sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
+
+	rate_control_rate_init(&sta->deflink);
+
+	/* If it fails, maybe we raced another insertion? */
+	if (sta_info_insert_rcu(sta))
+		return sta_info_get(sdata, addr);
+	return sta;
+}
+
+static void ieee80211_ocb_housekeeping(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
+
+	ocb_dbg(sdata, "Running ocb housekeeping\n");
+
+	ieee80211_sta_expire(sdata, IEEE80211_OCB_PEER_INACTIVITY_LIMIT);
+
+	mod_timer(&ifocb->housekeeping_timer,
+		  round_jiffies(jiffies + IEEE80211_OCB_HOUSEKEEPING_INTERVAL));
+}
+
+void ieee80211_ocb_work(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
+	struct sta_info *sta;
+
+	lockdep_assert_wiphy(sdata->local->hw.wiphy);
+
+	if (ifocb->joined != true)
+		return;
+
+	spin_lock_bh(&ifocb->incomplete_lock);
+	while (!list_empty(&ifocb->incomplete_stations)) {
+		sta = list_first_entry(&ifocb->incomplete_stations,
+				       struct sta_info, list);
+		list_del(&sta->list);
+		spin_unlock_bh(&ifocb->incomplete_lock);
+
+		ieee80211_ocb_finish_sta(sta);
+		rcu_read_unlock();
+		spin_lock_bh(&ifocb->incomplete_lock);
+	}
+	spin_unlock_bh(&ifocb->incomplete_lock);
+
+	if (test_and_clear_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags))
+		ieee80211_ocb_housekeeping(sdata);
+}
+
+static void ieee80211_ocb_housekeeping_timer(struct timer_list *t)
+{
+	struct ieee80211_sub_if_data *sdata =
+		timer_container_of(sdata, t, u.ocb.housekeeping_timer);
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
+
+	set_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags);
+
+	wiphy_work_queue(local->hw.wiphy, &sdata->work);
+}
+
+void ieee80211_ocb_setup_sdata(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
+
+	timer_setup(&ifocb->housekeeping_timer,
+		    ieee80211_ocb_housekeeping_timer, 0);
+	INIT_LIST_HEAD(&ifocb->incomplete_stations);
+	spin_lock_init(&ifocb->incomplete_lock);
+}
+
+int ieee80211_ocb_join(struct ieee80211_sub_if_data *sdata,
+		       struct ocb_setup *setup)
+{
+	struct ieee80211_chan_req chanreq = { .oper = setup->chandef };
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
+	u64 changed = BSS_CHANGED_OCB | BSS_CHANGED_BSSID;
+	int err;
+
+	lockdep_assert_wiphy(sdata->local->hw.wiphy);
+
+	if (ifocb->joined == true)
+		return -EINVAL;
+
+	sdata->deflink.operating_11g_mode = true;
+	sdata->deflink.smps_mode = IEEE80211_SMPS_OFF;
+	sdata->deflink.needed_rx_chains = sdata->local->rx_chains;
+
+	err = ieee80211_link_use_channel(&sdata->deflink, &chanreq,
+					 IEEE80211_CHANCTX_SHARED);
+	if (err)
+		return err;
+
+	ieee80211_bss_info_change_notify(sdata, changed);
+
+	ifocb->joined = true;
+
+	set_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags);
+	wiphy_work_queue(local->hw.wiphy, &sdata->work);
+
+	netif_carrier_on(sdata->dev);
+	return 0;
+}
+
+int ieee80211_ocb_leave(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
+	struct ieee80211_local *local = sdata->local;
+	struct sta_info *sta;
+
+	lockdep_assert_wiphy(sdata->local->hw.wiphy);
+
+	ifocb->joined = false;
+	sta_info_flush(sdata, -1);
+
+	spin_lock_bh(&ifocb->incomplete_lock);
+	while (!list_empty(&ifocb->incomplete_stations)) {
+		sta = list_first_entry(&ifocb->incomplete_stations,
+				       struct sta_info, list);
+		list_del(&sta->list);
+		spin_unlock_bh(&ifocb->incomplete_lock);
+
+		sta_info_free(local, sta);
+		spin_lock_bh(&ifocb->incomplete_lock);
+	}
+	spin_unlock_bh(&ifocb->incomplete_lock);
+
+	netif_carrier_off(sdata->dev);
+	clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
+	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_OCB);
+
+	ieee80211_link_release_channel(&sdata->deflink);
+
+	skb_queue_purge(&sdata->skb_queue);
+
+	timer_delete_sync(&sdata->u.ocb.housekeeping_timer);
+	/* If the timer fired while we waited for it, it will have
+	 * requeued the work. Now the work will be running again
+	 * but will not rearm the timer again because it checks
+	 * whether we are connected to the network or not -- at this
+	 * point we shouldn't be anymore.
+	 */
+
+	return 0;
+}