x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 359 insertions, 0 deletions

diff --git a/net/mac80211/he.c b/net/mac80211/he.c
new file mode 100644
index 000000000..5acf482c1
--- /dev/null
+++ b/net/mac80211/he.c
@@ -0,0 +1,359 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HE handling
+ *
+ * Copyright(c) 2017 Intel Deutschland GmbH
+ * Copyright(c) 2019-2026 Intel Corporation
+ */
+
+#include "ieee80211_i.h"
+#include "rate.h"
+
+static void
+ieee80211_update_from_he_6ghz_capa(const struct ieee80211_he_6ghz_capa *he_6ghz_capa,
+				   struct link_sta_info *link_sta)
+{
+	struct sta_info *sta = link_sta->sta;
+	enum ieee80211_smps_mode smps_mode;
+
+	if (sta->sdata->vif.type == NL80211_IFTYPE_AP ||
+	    sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
+		switch (le16_get_bits(he_6ghz_capa->capa,
+				      IEEE80211_HE_6GHZ_CAP_SM_PS)) {
+		case WLAN_HT_CAP_SM_PS_INVALID:
+		case WLAN_HT_CAP_SM_PS_STATIC:
+			smps_mode = IEEE80211_SMPS_STATIC;
+			break;
+		case WLAN_HT_CAP_SM_PS_DYNAMIC:
+			smps_mode = IEEE80211_SMPS_DYNAMIC;
+			break;
+		case WLAN_HT_CAP_SM_PS_DISABLED:
+			smps_mode = IEEE80211_SMPS_OFF;
+			break;
+		}
+
+		link_sta->pub->smps_mode = smps_mode;
+	} else {
+		link_sta->pub->smps_mode = IEEE80211_SMPS_OFF;
+	}
+
+	switch (le16_get_bits(he_6ghz_capa->capa,
+			      IEEE80211_HE_6GHZ_CAP_MAX_MPDU_LEN)) {
+	case IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454:
+		link_sta->pub->agg.max_amsdu_len = IEEE80211_MAX_MPDU_LEN_VHT_11454;
+		break;
+	case IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_7991:
+		link_sta->pub->agg.max_amsdu_len = IEEE80211_MAX_MPDU_LEN_VHT_7991;
+		break;
+	case IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_3895:
+	default:
+		link_sta->pub->agg.max_amsdu_len = IEEE80211_MAX_MPDU_LEN_VHT_3895;
+		break;
+	}
+
+	ieee80211_sta_recalc_aggregates(&sta->sta);
+
+	link_sta->pub->he_6ghz_capa = *he_6ghz_capa;
+}
+
+static void ieee80211_he_mcs_disable(__le16 *he_mcs)
+{
+	u32 i;
+
+	for (i = 0; i < 8; i++)
+		*he_mcs |= cpu_to_le16(IEEE80211_HE_MCS_NOT_SUPPORTED << i * 2);
+}
+
+static void ieee80211_he_mcs_intersection(__le16 *he_own_rx, __le16 *he_peer_rx,
+					  __le16 *he_own_tx, __le16 *he_peer_tx)
+{
+	u32 i;
+	u16 own_rx, own_tx, peer_rx, peer_tx;
+
+	for (i = 0; i < 8; i++) {
+		own_rx = le16_to_cpu(*he_own_rx);
+		own_rx = (own_rx >> i * 2) & IEEE80211_HE_MCS_NOT_SUPPORTED;
+
+		own_tx = le16_to_cpu(*he_own_tx);
+		own_tx = (own_tx >> i * 2) & IEEE80211_HE_MCS_NOT_SUPPORTED;
+
+		peer_rx = le16_to_cpu(*he_peer_rx);
+		peer_rx = (peer_rx >> i * 2) & IEEE80211_HE_MCS_NOT_SUPPORTED;
+
+		peer_tx = le16_to_cpu(*he_peer_tx);
+		peer_tx = (peer_tx >> i * 2) & IEEE80211_HE_MCS_NOT_SUPPORTED;
+
+		if (peer_tx != IEEE80211_HE_MCS_NOT_SUPPORTED) {
+			if (own_rx == IEEE80211_HE_MCS_NOT_SUPPORTED)
+				peer_tx = IEEE80211_HE_MCS_NOT_SUPPORTED;
+			else if (own_rx < peer_tx)
+				peer_tx = own_rx;
+		}
+
+		if (peer_rx != IEEE80211_HE_MCS_NOT_SUPPORTED) {
+			if (own_tx == IEEE80211_HE_MCS_NOT_SUPPORTED)
+				peer_rx = IEEE80211_HE_MCS_NOT_SUPPORTED;
+			else if (own_tx < peer_rx)
+				peer_rx = own_tx;
+		}
+
+		*he_peer_rx &=
+			~cpu_to_le16(IEEE80211_HE_MCS_NOT_SUPPORTED << i * 2);
+		*he_peer_rx |= cpu_to_le16(peer_rx << i * 2);
+
+		*he_peer_tx &=
+			~cpu_to_le16(IEEE80211_HE_MCS_NOT_SUPPORTED << i * 2);
+		*he_peer_tx |= cpu_to_le16(peer_tx << i * 2);
+	}
+}
+
+void
+_ieee80211_he_cap_ie_to_sta_he_cap(struct ieee80211_sub_if_data *sdata,
+				   const struct ieee80211_sta_he_cap *own_he_cap_ptr,
+				   const u8 *he_cap_ie, u8 he_cap_len,
+				   const struct ieee80211_he_6ghz_capa *he_6ghz_capa,
+				   struct link_sta_info *link_sta)
+{
+	struct ieee80211_sta_he_cap *he_cap = &link_sta->pub->he_cap;
+	struct ieee80211_sta_he_cap own_he_cap;
+	struct ieee80211_he_cap_elem *he_cap_ie_elem = (void *)he_cap_ie;
+	u8 he_ppe_size;
+	u8 mcs_nss_size;
+	u8 he_total_size;
+	bool own_160, peer_160, own_80p80, peer_80p80;
+
+	memset(he_cap, 0, sizeof(*he_cap));
+
+	if (!he_cap_ie || !own_he_cap_ptr || !own_he_cap_ptr->has_he)
+		return;
+
+	/* NDI station are using the capabilities from the NMI station */
+	if (WARN_ON_ONCE(sdata->vif.type == NL80211_IFTYPE_NAN_DATA))
+		return;
+
+	own_he_cap = *own_he_cap_ptr;
+
+	/* Make sure size is OK */
+	mcs_nss_size = ieee80211_he_mcs_nss_size(he_cap_ie_elem);
+	he_ppe_size =
+		ieee80211_he_ppe_size(he_cap_ie[sizeof(he_cap->he_cap_elem) +
+						mcs_nss_size],
+				      he_cap_ie_elem->phy_cap_info);
+	he_total_size = sizeof(he_cap->he_cap_elem) + mcs_nss_size +
+			he_ppe_size;
+	if (he_cap_len < he_total_size)
+		return;
+
+	memcpy(&he_cap->he_cap_elem, he_cap_ie, sizeof(he_cap->he_cap_elem));
+
+	/* HE Tx/Rx HE MCS NSS Support Field */
+	memcpy(&he_cap->he_mcs_nss_supp,
+	       &he_cap_ie[sizeof(he_cap->he_cap_elem)], mcs_nss_size);
+
+	/* Check if there are (optional) PPE Thresholds */
+	if (he_cap->he_cap_elem.phy_cap_info[6] &
+	    IEEE80211_HE_PHY_CAP6_PPE_THRESHOLD_PRESENT)
+		memcpy(he_cap->ppe_thres,
+		       &he_cap_ie[sizeof(he_cap->he_cap_elem) + mcs_nss_size],
+		       he_ppe_size);
+
+	he_cap->has_he = true;
+
+	if (he_6ghz_capa)
+		ieee80211_update_from_he_6ghz_capa(he_6ghz_capa, link_sta);
+
+	ieee80211_he_mcs_intersection(&own_he_cap.he_mcs_nss_supp.rx_mcs_80,
+				      &he_cap->he_mcs_nss_supp.rx_mcs_80,
+				      &own_he_cap.he_mcs_nss_supp.tx_mcs_80,
+				      &he_cap->he_mcs_nss_supp.tx_mcs_80);
+
+	own_160 = own_he_cap.he_cap_elem.phy_cap_info[0] &
+		  IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_160MHZ_IN_5G;
+	peer_160 = he_cap->he_cap_elem.phy_cap_info[0] &
+		   IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_160MHZ_IN_5G;
+
+	if (peer_160 && own_160) {
+		ieee80211_he_mcs_intersection(&own_he_cap.he_mcs_nss_supp.rx_mcs_160,
+					      &he_cap->he_mcs_nss_supp.rx_mcs_160,
+					      &own_he_cap.he_mcs_nss_supp.tx_mcs_160,
+					      &he_cap->he_mcs_nss_supp.tx_mcs_160);
+	} else if (peer_160 && !own_160) {
+		ieee80211_he_mcs_disable(&he_cap->he_mcs_nss_supp.rx_mcs_160);
+		ieee80211_he_mcs_disable(&he_cap->he_mcs_nss_supp.tx_mcs_160);
+		he_cap->he_cap_elem.phy_cap_info[0] &=
+			~IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_160MHZ_IN_5G;
+	}
+
+	own_80p80 = own_he_cap.he_cap_elem.phy_cap_info[0] &
+		    IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_80PLUS80_MHZ_IN_5G;
+	peer_80p80 = he_cap->he_cap_elem.phy_cap_info[0] &
+		     IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_80PLUS80_MHZ_IN_5G;
+
+	if (peer_80p80 && own_80p80) {
+		ieee80211_he_mcs_intersection(&own_he_cap.he_mcs_nss_supp.rx_mcs_80p80,
+					      &he_cap->he_mcs_nss_supp.rx_mcs_80p80,
+					      &own_he_cap.he_mcs_nss_supp.tx_mcs_80p80,
+					      &he_cap->he_mcs_nss_supp.tx_mcs_80p80);
+	} else if (peer_80p80 && !own_80p80) {
+		ieee80211_he_mcs_disable(&he_cap->he_mcs_nss_supp.rx_mcs_80p80);
+		ieee80211_he_mcs_disable(&he_cap->he_mcs_nss_supp.tx_mcs_80p80);
+		he_cap->he_cap_elem.phy_cap_info[0] &=
+			~IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_80PLUS80_MHZ_IN_5G;
+	}
+}
+
+void
+ieee80211_he_cap_ie_to_sta_he_cap(struct ieee80211_sub_if_data *sdata,
+				  struct ieee80211_supported_band *sband,
+				  const u8 *he_cap_ie, u8 he_cap_len,
+				  const struct ieee80211_he_6ghz_capa *he_6ghz_capa,
+				  struct link_sta_info *link_sta)
+{
+	const struct ieee80211_sta_he_cap *own_he_cap =
+		ieee80211_get_he_iftype_cap_vif(sband, &sdata->vif);
+
+	_ieee80211_he_cap_ie_to_sta_he_cap(sdata, own_he_cap, he_cap_ie,
+					   he_cap_len,
+					   (sband->band == NL80211_BAND_6GHZ) ?
+						he_6ghz_capa : NULL,
+					   link_sta);
+}
+
+void
+ieee80211_he_op_ie_to_bss_conf(struct ieee80211_vif *vif,
+			const struct ieee80211_he_operation *he_op_ie)
+{
+	memset(&vif->bss_conf.he_oper, 0, sizeof(vif->bss_conf.he_oper));
+	if (!he_op_ie)
+		return;
+
+	vif->bss_conf.he_oper.params = __le32_to_cpu(he_op_ie->he_oper_params);
+	vif->bss_conf.he_oper.nss_set = __le16_to_cpu(he_op_ie->he_mcs_nss_set);
+}
+
+void
+ieee80211_he_spr_ie_to_bss_conf(struct ieee80211_vif *vif,
+				const struct ieee80211_he_spr *he_spr_ie_elem)
+{
+	struct ieee80211_he_obss_pd *he_obss_pd =
+					&vif->bss_conf.he_obss_pd;
+	const u8 *data;
+
+	memset(he_obss_pd, 0, sizeof(*he_obss_pd));
+
+	if (!he_spr_ie_elem)
+		return;
+
+	he_obss_pd->sr_ctrl = he_spr_ie_elem->he_sr_control;
+	data = he_spr_ie_elem->optional;
+
+	if (he_spr_ie_elem->he_sr_control &
+	    IEEE80211_HE_SPR_NON_SRG_OFFSET_PRESENT)
+		he_obss_pd->non_srg_max_offset = *data++;
+
+	if (he_spr_ie_elem->he_sr_control &
+	    IEEE80211_HE_SPR_SRG_INFORMATION_PRESENT) {
+		he_obss_pd->min_offset = *data++;
+		he_obss_pd->max_offset = *data++;
+		memcpy(he_obss_pd->bss_color_bitmap, data, 8);
+		data += 8;
+		memcpy(he_obss_pd->partial_bssid_bitmap, data, 8);
+		he_obss_pd->enable = true;
+	}
+}
+
+bool ieee80211_prepare_rx_omi_bw(struct ieee80211_link_sta *pub_link_sta,
+				 enum ieee80211_sta_rx_bandwidth bw)
+{
+	struct sta_info *sta = container_of(pub_link_sta->sta,
+					    struct sta_info, sta);
+	struct ieee80211_local *local = sta->sdata->local;
+	struct link_sta_info *link_sta =
+		sdata_dereference(sta->link[pub_link_sta->link_id], sta->sdata);
+	struct ieee80211_link_data *link =
+		sdata_dereference(sta->sdata->link[pub_link_sta->link_id],
+				  sta->sdata);
+	struct ieee80211_chanctx_conf *conf;
+	struct ieee80211_chanctx *chanctx;
+	bool ret;
+
+	if (WARN_ON(!link || !link_sta || link_sta->pub != pub_link_sta))
+		return false;
+
+	conf = sdata_dereference(link->conf->chanctx_conf, sta->sdata);
+	if (WARN_ON(!conf))
+		return false;
+
+	trace_api_prepare_rx_omi_bw(local, sta->sdata, link_sta, bw);
+
+	chanctx = container_of(conf, typeof(*chanctx), conf);
+
+	if (link_sta->rx_omi_bw_staging == bw) {
+		ret = false;
+		goto trace;
+	}
+
+	/* must call this API in pairs */
+	if (WARN_ON(link_sta->rx_omi_bw_tx != link_sta->rx_omi_bw_staging ||
+		    link_sta->rx_omi_bw_rx != link_sta->rx_omi_bw_staging)) {
+		ret = false;
+		goto trace;
+	}
+
+	if (bw < link_sta->rx_omi_bw_staging) {
+		link_sta->rx_omi_bw_tx = bw;
+		ieee80211_link_sta_update_rc_bw(link, link_sta);
+	} else {
+		link_sta->rx_omi_bw_rx = bw;
+		ieee80211_recalc_chanctx_min_def(local, chanctx);
+	}
+
+	link_sta->rx_omi_bw_staging = bw;
+	ret = true;
+trace:
+	trace_api_return_bool(local, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ieee80211_prepare_rx_omi_bw);
+
+void ieee80211_finalize_rx_omi_bw(struct ieee80211_link_sta *pub_link_sta)
+{
+	struct sta_info *sta = container_of(pub_link_sta->sta,
+					    struct sta_info, sta);
+	struct ieee80211_local *local = sta->sdata->local;
+	struct link_sta_info *link_sta =
+		sdata_dereference(sta->link[pub_link_sta->link_id], sta->sdata);
+	struct ieee80211_link_data *link =
+		sdata_dereference(sta->sdata->link[pub_link_sta->link_id],
+				  sta->sdata);
+	struct ieee80211_chanctx_conf *conf;
+	struct ieee80211_chanctx *chanctx;
+
+	if (WARN_ON(!link || !link_sta || link_sta->pub != pub_link_sta))
+		return;
+
+	conf = sdata_dereference(link->conf->chanctx_conf, sta->sdata);
+	if (WARN_ON(!conf))
+		return;
+
+	trace_api_finalize_rx_omi_bw(local, sta->sdata, link_sta);
+
+	chanctx = container_of(conf, typeof(*chanctx), conf);
+
+	if (link_sta->rx_omi_bw_tx != link_sta->rx_omi_bw_staging) {
+		/* rate control in finalize only when widening bandwidth */
+		WARN_ON(link_sta->rx_omi_bw_tx > link_sta->rx_omi_bw_staging);
+		link_sta->rx_omi_bw_tx = link_sta->rx_omi_bw_staging;
+		ieee80211_link_sta_update_rc_bw(link, link_sta);
+	}
+
+	if (link_sta->rx_omi_bw_rx != link_sta->rx_omi_bw_staging) {
+		/* channel context in finalize only when narrowing bandwidth */
+		WARN_ON(link_sta->rx_omi_bw_rx < link_sta->rx_omi_bw_staging);
+		link_sta->rx_omi_bw_rx = link_sta->rx_omi_bw_staging;
+		ieee80211_recalc_chanctx_min_def(local, chanctx);
+	}
+
+	trace_api_return_void(local);
+}
+EXPORT_SYMBOL_GPL(ieee80211_finalize_rx_omi_bw);