From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions 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) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- Documentation/driver-api/80211/cfg80211.rst | 178 +++++++++++++++ Documentation/driver-api/80211/index.rst | 10 + Documentation/driver-api/80211/introduction.rst | 17 ++ .../driver-api/80211/mac80211-advanced.rst | 239 +++++++++++++++++++++ Documentation/driver-api/80211/mac80211.rst | 155 +++++++++++++ 5 files changed, 599 insertions(+) create mode 100644 Documentation/driver-api/80211/cfg80211.rst create mode 100644 Documentation/driver-api/80211/index.rst create mode 100644 Documentation/driver-api/80211/introduction.rst create mode 100644 Documentation/driver-api/80211/mac80211-advanced.rst create mode 100644 Documentation/driver-api/80211/mac80211.rst (limited to 'Documentation/driver-api/80211') diff --git a/Documentation/driver-api/80211/cfg80211.rst b/Documentation/driver-api/80211/cfg80211.rst new file mode 100644 index 000000000..836f609c3 --- /dev/null +++ b/Documentation/driver-api/80211/cfg80211.rst @@ -0,0 +1,178 @@ +================== +cfg80211 subsystem +================== + +.. kernel-doc:: include/net/cfg80211.h + :doc: Introduction + +Device registration +=================== + +.. kernel-doc:: include/net/cfg80211.h + :doc: Device registration + +.. kernel-doc:: include/net/cfg80211.h + :functions: + ieee80211_channel_flags + ieee80211_channel + ieee80211_rate_flags + ieee80211_rate + ieee80211_sta_ht_cap + ieee80211_supported_band + cfg80211_signal_type + wiphy_params_flags + wiphy_flags + wiphy + wireless_dev + wiphy_new + wiphy_read_of_freq_limits + wiphy_register + wiphy_unregister + wiphy_free + wiphy_name + wiphy_dev + wiphy_priv + priv_to_wiphy + set_wiphy_dev + wdev_priv + ieee80211_iface_limit + ieee80211_iface_combination + cfg80211_check_combinations + +Actions and configuration +========================= + +.. kernel-doc:: include/net/cfg80211.h + :doc: Actions and configuration + +.. kernel-doc:: include/net/cfg80211.h + :functions: + cfg80211_ops + vif_params + key_params + survey_info_flags + survey_info + cfg80211_beacon_data + cfg80211_ap_settings + station_parameters + rate_info_flags + rate_info + station_info + monitor_flags + mpath_info_flags + mpath_info + bss_parameters + ieee80211_txq_params + cfg80211_crypto_settings + cfg80211_auth_request + cfg80211_assoc_request + cfg80211_deauth_request + cfg80211_disassoc_request + cfg80211_ibss_params + cfg80211_connect_params + cfg80211_pmksa + cfg80211_rx_mlme_mgmt + cfg80211_auth_timeout + cfg80211_rx_assoc_resp + cfg80211_assoc_timeout + cfg80211_tx_mlme_mgmt + cfg80211_ibss_joined + cfg80211_connect_resp_params + cfg80211_connect_done + cfg80211_connect_result + cfg80211_connect_bss + cfg80211_connect_timeout + cfg80211_roamed + cfg80211_disconnected + cfg80211_ready_on_channel + cfg80211_remain_on_channel_expired + cfg80211_new_sta + cfg80211_rx_mgmt + cfg80211_mgmt_tx_status + cfg80211_cqm_rssi_notify + cfg80211_cqm_pktloss_notify + cfg80211_michael_mic_failure + +Scanning and BSS list handling +============================== + +.. kernel-doc:: include/net/cfg80211.h + :doc: Scanning and BSS list handling + +.. kernel-doc:: include/net/cfg80211.h + :functions: + cfg80211_ssid + cfg80211_scan_request + cfg80211_scan_done + cfg80211_bss + cfg80211_inform_bss + cfg80211_inform_bss_frame_data + cfg80211_inform_bss_data + cfg80211_unlink_bss + cfg80211_find_ie + ieee80211_bss_get_ie + +Utility functions +================= + +.. kernel-doc:: include/net/cfg80211.h + :doc: Utility functions + +.. kernel-doc:: include/net/cfg80211.h + :functions: + ieee80211_channel_to_frequency + ieee80211_frequency_to_channel + ieee80211_get_channel + ieee80211_get_response_rate + ieee80211_hdrlen + ieee80211_get_hdrlen_from_skb + ieee80211_radiotap_iterator + +Data path helpers +================= + +.. kernel-doc:: include/net/cfg80211.h + :doc: Data path helpers + +.. kernel-doc:: include/net/cfg80211.h + :functions: + ieee80211_data_to_8023 + ieee80211_amsdu_to_8023s + cfg80211_classify8021d + +Regulatory enforcement infrastructure +===================================== + +.. kernel-doc:: include/net/cfg80211.h + :doc: Regulatory enforcement infrastructure + +.. kernel-doc:: include/net/cfg80211.h + :functions: + regulatory_hint + wiphy_apply_custom_regulatory + freq_reg_info + +RFkill integration +================== + +.. kernel-doc:: include/net/cfg80211.h + :doc: RFkill integration + +.. kernel-doc:: include/net/cfg80211.h + :functions: + wiphy_rfkill_set_hw_state + wiphy_rfkill_start_polling + wiphy_rfkill_stop_polling + +Test mode +========= + +.. kernel-doc:: include/net/cfg80211.h + :doc: Test mode + +.. kernel-doc:: include/net/cfg80211.h + :functions: + cfg80211_testmode_alloc_reply_skb + cfg80211_testmode_reply + cfg80211_testmode_alloc_event_skb + cfg80211_testmode_event diff --git a/Documentation/driver-api/80211/index.rst b/Documentation/driver-api/80211/index.rst new file mode 100644 index 000000000..62305e9c3 --- /dev/null +++ b/Documentation/driver-api/80211/index.rst @@ -0,0 +1,10 @@ +===================================== +Linux 802.11 Driver Developer's Guide +===================================== + +.. toctree:: + + introduction + cfg80211 + mac80211 + mac80211-advanced diff --git a/Documentation/driver-api/80211/introduction.rst b/Documentation/driver-api/80211/introduction.rst new file mode 100644 index 000000000..4938fa876 --- /dev/null +++ b/Documentation/driver-api/80211/introduction.rst @@ -0,0 +1,17 @@ +============ +Introduction +============ + +Explaining wireless 802.11 networking in the Linux kernel + +Copyright 2007-2009 Johannes Berg + +These books attempt to give a description of the various subsystems +that play a role in 802.11 wireless networking in Linux. Since these +books are for kernel developers they attempts to document the +structures and functions used in the kernel as well as giving a +higher-level overview. + +The reader is expected to be familiar with the 802.11 standard as +published by the IEEE in 802.11-2007 (or possibly later versions). +References to this standard will be given as "802.11-2007 8.1.5". diff --git a/Documentation/driver-api/80211/mac80211-advanced.rst b/Documentation/driver-api/80211/mac80211-advanced.rst new file mode 100644 index 000000000..f8df7b3af --- /dev/null +++ b/Documentation/driver-api/80211/mac80211-advanced.rst @@ -0,0 +1,239 @@ +============================= +mac80211 subsystem (advanced) +============================= + +Information contained within this part of the book is of interest only +for advanced interaction of mac80211 with drivers to exploit more +hardware capabilities and improve performance. + +LED support +=========== + +Mac80211 supports various ways of blinking LEDs. Wherever possible, +device LEDs should be exposed as LED class devices and hooked up to the +appropriate trigger, which will then be triggered appropriately by +mac80211. + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_get_tx_led_name + ieee80211_get_rx_led_name + ieee80211_get_assoc_led_name + ieee80211_get_radio_led_name + ieee80211_tpt_blink + ieee80211_tpt_led_trigger_flags + ieee80211_create_tpt_led_trigger + +Hardware crypto acceleration +============================ + +.. kernel-doc:: include/net/mac80211.h + :doc: Hardware crypto acceleration + +.. kernel-doc:: include/net/mac80211.h + :functions: + set_key_cmd + ieee80211_key_conf + ieee80211_key_flags + ieee80211_get_tkip_p1k + ieee80211_get_tkip_p1k_iv + ieee80211_get_tkip_p2k + +Powersave support +================= + +.. kernel-doc:: include/net/mac80211.h + :doc: Powersave support + +Beacon filter support +===================== + +.. kernel-doc:: include/net/mac80211.h + :doc: Beacon filter support + +.. kernel-doc:: include/net/mac80211.h + :functions: ieee80211_beacon_loss + +Multiple queues and QoS support +=============================== + +TBD + +.. kernel-doc:: include/net/mac80211.h + :functions: ieee80211_tx_queue_params + +Access point mode support +========================= + +TBD + +Some parts of the if_conf should be discussed here instead + +Insert notes about VLAN interfaces with hw crypto here or in the hw +crypto chapter. + +support for powersaving clients +------------------------------- + +.. kernel-doc:: include/net/mac80211.h + :doc: AP support for powersaving clients + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_get_buffered_bc + ieee80211_beacon_get + ieee80211_sta_eosp + ieee80211_frame_release_type + ieee80211_sta_ps_transition + ieee80211_sta_ps_transition_ni + ieee80211_sta_set_buffered + ieee80211_sta_block_awake + +Supporting multiple virtual interfaces +====================================== + +TBD + +Note: WDS with identical MAC address should almost always be OK + +Insert notes about having multiple virtual interfaces with different MAC +addresses here, note which configurations are supported by mac80211, add +notes about supporting hw crypto with it. + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_iterate_active_interfaces + ieee80211_iterate_active_interfaces_atomic + +Station handling +================ + +TODO + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_sta + sta_notify_cmd + ieee80211_find_sta + ieee80211_find_sta_by_ifaddr + +Hardware scan offload +===================== + +TBD + +.. kernel-doc:: include/net/mac80211.h + :functions: ieee80211_scan_completed + +Aggregation +=========== + +TX A-MPDU aggregation +--------------------- + +.. kernel-doc:: net/mac80211/agg-tx.c + :doc: TX A-MPDU aggregation + +.. WARNING: DOCPROC directive not supported: !Cnet/mac80211/agg-tx.c + +RX A-MPDU aggregation +--------------------- + +.. kernel-doc:: net/mac80211/agg-rx.c + :doc: RX A-MPDU aggregation + +.. WARNING: DOCPROC directive not supported: !Cnet/mac80211/agg-rx.c + +.. kernel-doc:: include/net/mac80211.h + :functions: ieee80211_ampdu_mlme_action + +Spatial Multiplexing Powersave (SMPS) +===================================== + +.. kernel-doc:: include/net/mac80211.h + :doc: Spatial multiplexing power save + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_request_smps + ieee80211_smps_mode + +TBD + +This part of the book describes the rate control algorithm interface and +how it relates to mac80211 and drivers. + +Rate Control API +================ + +TBD + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_start_tx_ba_session + ieee80211_start_tx_ba_cb_irqsafe + ieee80211_stop_tx_ba_session + ieee80211_stop_tx_ba_cb_irqsafe + ieee80211_rate_control_changed + ieee80211_tx_rate_control + +TBD + +This part of the book describes mac80211 internals. + +Key handling +============ + +Key handling basics +------------------- + +.. kernel-doc:: net/mac80211/key.c + :doc: Key handling basics + +MORE TBD +-------- + +TBD + +Receive processing +================== + +TBD + +Transmit processing +=================== + +TBD + +Station info handling +===================== + +Programming information +----------------------- + +.. kernel-doc:: net/mac80211/sta_info.h + :functions: + sta_info + ieee80211_sta_info_flags + +STA information lifetime rules +------------------------------ + +.. kernel-doc:: net/mac80211/sta_info.c + :doc: STA information lifetime rules + +Aggregation Functions +===================== + +.. kernel-doc:: net/mac80211/sta_info.h + :functions: + sta_ampdu_mlme + tid_ampdu_tx + tid_ampdu_rx + +Synchronisation Functions +========================= + +TBD + +Locking, lots of RCU diff --git a/Documentation/driver-api/80211/mac80211.rst b/Documentation/driver-api/80211/mac80211.rst new file mode 100644 index 000000000..e38a22040 --- /dev/null +++ b/Documentation/driver-api/80211/mac80211.rst @@ -0,0 +1,155 @@ +=========================== +mac80211 subsystem (basics) +=========================== + +You should read and understand the information contained within this +part of the book while implementing a mac80211 driver. In some chapters, +advanced usage is noted, those may be skipped if this isn't needed. + +This part of the book only covers station and monitor mode +functionality, additional information required to implement the other +modes is covered in the second part of the book. + +Basic hardware handling +======================= + +TBD + +This chapter shall contain information on getting a hw struct allocated +and registered with mac80211. + +Since it is required to allocate rates/modes before registering a hw +struct, this chapter shall also contain information on setting up the +rate/mode structs. + +Additionally, some discussion about the callbacks and the general +programming model should be in here, including the definition of +ieee80211_ops which will be referred to a lot. + +Finally, a discussion of hardware capabilities should be done with +references to other parts of the book. + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_hw + ieee80211_hw_flags + SET_IEEE80211_DEV + SET_IEEE80211_PERM_ADDR + ieee80211_ops + ieee80211_alloc_hw + ieee80211_register_hw + ieee80211_unregister_hw + ieee80211_free_hw + +PHY configuration +================= + +TBD + +This chapter should describe PHY handling including start/stop callbacks +and the various structures used. + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_conf + ieee80211_conf_flags + +Virtual interfaces +================== + +TBD + +This chapter should describe virtual interface basics that are relevant +to the driver (VLANs, MGMT etc are not.) It should explain the use of +the add_iface/remove_iface callbacks as well as the interface +configuration callbacks. + +Things related to AP mode should be discussed there. + +Things related to supporting multiple interfaces should be in the +appropriate chapter, a BIG FAT note should be here about this though and +the recommendation to allow only a single interface in STA mode at +first! + +.. kernel-doc:: include/net/mac80211.h + :functions: ieee80211_vif + +Receive and transmit processing +=============================== + +what should be here +------------------- + +TBD + +This should describe the receive and transmit paths in mac80211/the +drivers as well as transmit status handling. + +Frame format +------------ + +.. kernel-doc:: include/net/mac80211.h + :doc: Frame format + +Packet alignment +---------------- + +.. kernel-doc:: net/mac80211/rx.c + :doc: Packet alignment + +Calling into mac80211 from interrupts +------------------------------------- + +.. kernel-doc:: include/net/mac80211.h + :doc: Calling mac80211 from interrupts + +functions/definitions +--------------------- + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_rx_status + mac80211_rx_encoding_flags + mac80211_rx_flags + mac80211_tx_info_flags + mac80211_tx_control_flags + mac80211_rate_control_flags + ieee80211_tx_rate + ieee80211_tx_info + ieee80211_tx_info_clear_status + ieee80211_rx + ieee80211_rx_ni + ieee80211_rx_irqsafe + ieee80211_tx_status_skb + ieee80211_tx_status_ni + ieee80211_tx_status_irqsafe + ieee80211_rts_get + ieee80211_rts_duration + ieee80211_ctstoself_get + ieee80211_ctstoself_duration + ieee80211_generic_frame_duration + ieee80211_wake_queue + ieee80211_stop_queue + ieee80211_wake_queues + ieee80211_stop_queues + ieee80211_queue_stopped + +Frame filtering +=============== + +.. kernel-doc:: include/net/mac80211.h + :doc: Frame filtering + +.. kernel-doc:: include/net/mac80211.h + :functions: ieee80211_filter_flags + +The mac80211 workqueue +====================== + +.. kernel-doc:: include/net/mac80211.h + :doc: mac80211 workqueue + +.. kernel-doc:: include/net/mac80211.h + :functions: + ieee80211_queue_work + ieee80211_queue_delayed_work -- cgit v1.3.1