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, 102 insertions, 0 deletions

diff --git a/net/mac80211/eht.c b/net/mac80211/eht.c
new file mode 100644
index 000000000..23fe82df6
--- /dev/null
+++ b/net/mac80211/eht.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * EHT handling
+ *
+ * Copyright(c) 2021-2026 Intel Corporation
+ */
+
+#include "driver-ops.h"
+#include "ieee80211_i.h"
+
+void
+ieee80211_eht_cap_ie_to_sta_eht_cap(struct ieee80211_sub_if_data *sdata,
+				    struct ieee80211_supported_band *sband,
+				    const u8 *he_cap_ie, u8 he_cap_len,
+				    const struct ieee80211_eht_cap_elem *eht_cap_ie_elem,
+				    u8 eht_cap_len,
+				    struct link_sta_info *link_sta)
+{
+	struct ieee80211_sta_eht_cap *eht_cap = &link_sta->pub->eht_cap;
+	struct ieee80211_he_cap_elem *he_cap_ie_elem = (void *)he_cap_ie;
+	u8 eht_ppe_size = 0;
+	u8 mcs_nss_size;
+	u8 eht_total_size = sizeof(eht_cap->eht_cap_elem);
+	u8 *pos = (u8 *)eht_cap_ie_elem;
+
+	memset(eht_cap, 0, sizeof(*eht_cap));
+
+	if (!eht_cap_ie_elem ||
+	    !ieee80211_get_eht_iftype_cap_vif(sband, &sdata->vif))
+		return;
+
+	mcs_nss_size = ieee80211_eht_mcs_nss_size(he_cap_ie_elem,
+						  &eht_cap_ie_elem->fixed,
+						  sdata->vif.type ==
+							NL80211_IFTYPE_STATION);
+
+	eht_total_size += mcs_nss_size;
+
+	/* Calculate the PPE thresholds length only if the header is present */
+	if (eht_cap_ie_elem->fixed.phy_cap_info[5] &
+			IEEE80211_EHT_PHY_CAP5_PPE_THRESHOLD_PRESENT) {
+		u16 eht_ppe_hdr;
+
+		if (eht_cap_len < eht_total_size + sizeof(u16))
+			return;
+
+		eht_ppe_hdr = get_unaligned_le16(eht_cap_ie_elem->optional + mcs_nss_size);
+		eht_ppe_size =
+			ieee80211_eht_ppe_size(eht_ppe_hdr,
+					       eht_cap_ie_elem->fixed.phy_cap_info);
+		eht_total_size += eht_ppe_size;
+
+		/* we calculate as if NSS > 8 are valid, but don't handle that */
+		if (eht_ppe_size > sizeof(eht_cap->eht_ppe_thres))
+			return;
+	}
+
+	if (eht_cap_len < eht_total_size)
+		return;
+
+	/* Copy the static portion of the EHT capabilities */
+	memcpy(&eht_cap->eht_cap_elem, pos, sizeof(eht_cap->eht_cap_elem));
+	pos += sizeof(eht_cap->eht_cap_elem);
+
+	/* Copy MCS/NSS which depends on the peer capabilities */
+	memset(&eht_cap->eht_mcs_nss_supp, 0,
+	       sizeof(eht_cap->eht_mcs_nss_supp));
+	memcpy(&eht_cap->eht_mcs_nss_supp, pos, mcs_nss_size);
+
+	if (eht_ppe_size)
+		memcpy(eht_cap->eht_ppe_thres,
+		       &eht_cap_ie_elem->optional[mcs_nss_size],
+		       eht_ppe_size);
+
+	eht_cap->has_eht = true;
+
+	/*
+	 * The MPDU length bits are reserved on all but 2.4 GHz and get set via
+	 * VHT (5 GHz) or HE (6 GHz) capabilities.
+	 */
+	if (sband->band != NL80211_BAND_2GHZ)
+		return;
+
+	switch (u8_get_bits(eht_cap->eht_cap_elem.mac_cap_info[0],
+			    IEEE80211_EHT_MAC_CAP0_MAX_MPDU_LEN_MASK)) {
+	case IEEE80211_EHT_MAC_CAP0_MAX_MPDU_LEN_11454:
+		link_sta->pub->agg.max_amsdu_len =
+			IEEE80211_MAX_MPDU_LEN_VHT_11454;
+		break;
+	case IEEE80211_EHT_MAC_CAP0_MAX_MPDU_LEN_7991:
+		link_sta->pub->agg.max_amsdu_len =
+			IEEE80211_MAX_MPDU_LEN_VHT_7991;
+		break;
+	case IEEE80211_EHT_MAC_CAP0_MAX_MPDU_LEN_3895:
+	default:
+		link_sta->pub->agg.max_amsdu_len =
+			IEEE80211_MAX_MPDU_LEN_VHT_3895;
+		break;
+	}
+
+	ieee80211_sta_recalc_aggregates(&link_sta->sta->sta);
+}