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, 200 insertions, 0 deletions

diff --git a/net/mac80211/pm.c b/net/mac80211/pm.c
new file mode 100644
index 000000000..5a508d99e
--- /dev/null
+++ b/net/mac80211/pm.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Portions
+ * Copyright (C) 2020-2021, 2023-2024 Intel Corporation
+ */
+#include <net/mac80211.h>
+#include <net/rtnetlink.h>
+
+#include "ieee80211_i.h"
+#include "mesh.h"
+#include "driver-ops.h"
+#include "led.h"
+
+static void ieee80211_sched_scan_cancel(struct ieee80211_local *local)
+{
+	if (ieee80211_request_sched_scan_stop(local))
+		return;
+	cfg80211_sched_scan_stopped_locked(local->hw.wiphy, 0);
+}
+
+int __ieee80211_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+	struct ieee80211_sub_if_data *sdata;
+	struct sta_info *sta;
+
+	if (!local->open_count)
+		goto suspend;
+
+	local->suspending = true;
+	mb(); /* make suspending visible before any cancellation */
+
+	ieee80211_scan_cancel(local);
+
+	ieee80211_dfs_cac_cancel(local, NULL);
+
+	ieee80211_roc_purge(local, NULL);
+
+	ieee80211_del_virtual_monitor(local);
+
+	if (ieee80211_hw_check(hw, AMPDU_AGGREGATION) &&
+	    !(wowlan && wowlan->any)) {
+		lockdep_assert_wiphy(local->hw.wiphy);
+		list_for_each_entry(sta, &local->sta_list, list) {
+			set_sta_flag(sta, WLAN_STA_BLOCK_BA);
+			ieee80211_sta_tear_down_BA_sessions(
+					sta, AGG_STOP_LOCAL_REQUEST);
+		}
+	}
+
+	/* keep sched_scan only in case of 'any' trigger */
+	if (!(wowlan && wowlan->any))
+		ieee80211_sched_scan_cancel(local);
+
+	ieee80211_stop_queues_by_reason(hw,
+					IEEE80211_MAX_QUEUE_MAP,
+					IEEE80211_QUEUE_STOP_REASON_SUSPEND,
+					false);
+
+	/* flush out all packets */
+	synchronize_net();
+
+	ieee80211_flush_queues(local, NULL, true);
+
+	local->quiescing = true;
+	/* make quiescing visible to timers everywhere */
+	mb();
+
+	flush_workqueue(local->workqueue);
+
+	/* Don't try to run timers while suspended. */
+	timer_delete_sync(&local->sta_cleanup);
+
+	 /*
+	 * Note that this particular timer doesn't need to be
+	 * restarted at resume.
+	 */
+	wiphy_work_cancel(local->hw.wiphy, &local->dynamic_ps_enable_work);
+	timer_delete_sync(&local->dynamic_ps_timer);
+
+	local->wowlan = wowlan;
+	if (local->wowlan) {
+		int err;
+
+		/* Drivers don't expect to suspend while some operations like
+		 * authenticating or associating are in progress. It doesn't
+		 * make sense anyway to accept that, since the authentication
+		 * or association would never finish since the driver can't do
+		 * that on its own.
+		 * Thus, clean up in-progress auth/assoc first.
+		 */
+		list_for_each_entry(sdata, &local->interfaces, list) {
+			if (!ieee80211_sdata_running(sdata))
+				continue;
+			if (sdata->vif.type != NL80211_IFTYPE_STATION)
+				continue;
+			ieee80211_mgd_quiesce(sdata);
+			/* If suspended during TX in progress, and wowlan
+			 * is enabled (connection will be active) there
+			 * can be a race where the driver is put out
+			 * of power-save due to TX and during suspend
+			 * dynamic_ps_timer is cancelled and TX packet
+			 * is flushed, leaving the driver in ACTIVE even
+			 * after resuming until dynamic_ps_timer puts
+			 * driver back in DOZE.
+			 */
+			if (sdata->u.mgd.associated &&
+			    sdata->u.mgd.powersave &&
+			     !(local->hw.conf.flags & IEEE80211_CONF_PS)) {
+				local->hw.conf.flags |= IEEE80211_CONF_PS;
+				ieee80211_hw_config(local, -1,
+						    IEEE80211_CONF_CHANGE_PS);
+			}
+		}
+
+		err = drv_suspend(local, wowlan);
+		if (err < 0) {
+			local->quiescing = false;
+			local->wowlan = false;
+			if (ieee80211_hw_check(hw, AMPDU_AGGREGATION)) {
+				lockdep_assert_wiphy(local->hw.wiphy);
+				list_for_each_entry(sta,
+						    &local->sta_list, list) {
+					clear_sta_flag(sta, WLAN_STA_BLOCK_BA);
+				}
+			}
+			ieee80211_wake_queues_by_reason(hw,
+					IEEE80211_MAX_QUEUE_MAP,
+					IEEE80211_QUEUE_STOP_REASON_SUSPEND,
+					false);
+			return err;
+		} else if (err > 0) {
+			WARN_ON(err != 1);
+			/* cfg80211 will call back into mac80211 to disconnect
+			 * all interfaces, allow that to proceed properly
+			 */
+			ieee80211_wake_queues_by_reason(hw,
+					IEEE80211_MAX_QUEUE_MAP,
+					IEEE80211_QUEUE_STOP_REASON_SUSPEND,
+					false);
+			return err;
+		} else {
+			goto suspend;
+		}
+	}
+
+	/* remove all interfaces that were created in the driver */
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		if (!ieee80211_sdata_running(sdata))
+			continue;
+		switch (sdata->vif.type) {
+		case NL80211_IFTYPE_AP_VLAN:
+		case NL80211_IFTYPE_MONITOR:
+			continue;
+		case NL80211_IFTYPE_STATION:
+			ieee80211_mgd_quiesce(sdata);
+			break;
+		default:
+			break;
+		}
+
+		wiphy_delayed_work_flush(local->hw.wiphy,
+					 &sdata->dec_tailroom_needed_wk);
+		drv_remove_interface(local, sdata);
+	}
+
+	/*
+	 * We disconnected on all interfaces before suspend, all channel
+	 * contexts should be released.
+	 */
+	WARN_ON(!list_empty(&local->chanctx_list));
+
+	/* stop hardware - this must stop RX */
+	ieee80211_stop_device(local, true);
+
+ suspend:
+	local->suspended = true;
+	/* need suspended to be visible before quiescing is false */
+	barrier();
+	local->quiescing = false;
+	local->suspending = false;
+
+	return 0;
+}
+
+/*
+ * __ieee80211_resume() is a static inline which just calls
+ * ieee80211_reconfig(), which is also needed for hardware
+ * hang/firmware failure/etc. recovery.
+ */
+
+void ieee80211_report_wowlan_wakeup(struct ieee80211_vif *vif,
+				    struct cfg80211_wowlan_wakeup *wakeup,
+				    gfp_t gfp)
+{
+	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+
+	cfg80211_report_wowlan_wakeup(&sdata->wdev, wakeup, gfp);
+}
+EXPORT_SYMBOL(ieee80211_report_wowlan_wakeup);