Wen Gong <quic_wgong@xxxxxxxxxxx> wrote: > When WMI_REG_CHAN_LIST_CC_EVENTID arrived, ath11k queue regd_update_work > to workqueue of mac80211, then ath11k_regd_update start to acquire the > rtnl_mutex by rtnl_lock, if the lock is already acquired by other thread, > then it is easy happen deadlock, it is very easy to happen that while > it is in progress of wlan shut down. > > Below is 3 type of deadlock. > > Type 1: > cfg80211_rfkill_set_block of thread A called rtnl_lock and acquired > the rtnl_mutex, then ath11k_regd_update begin run in workqueue of > mac80211, but it can not acquire the rtnl_mutex by rtnl_lock and enter > sleep state. Then thread A continue run and called arrive function > ieee80211_stop_device which flush_workqueue of mac80211, it is the same > workqueue which is running ath11k_regd_update, so deadlock happened. > Thread A wait all work complete in workqueue of mac80211, but the work > of ath11k_regd_update is waiting Thread A release the rtnl_mutex. > > workqueue of ath11k_regd_update > [ 363.570365] INFO: task kworker/u16:3:240 blocked for more than 120 seconds. > [ 363.570369] Tainted: G W 5.7.0-rc7-wt-ath+ #3 > [ 363.570372] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 363.570376] kworker/u16:3 D 0 240 2 0x80004000 > [ 363.570412] Workqueue: phy0 ath11k_regd_update_work [ath11k] > [ 363.570415] Call Trace: > [ 363.570423] __schedule+0x44e/0x6f0 > [ 363.570432] schedule+0x4a/0xb0 > [ 363.570439] schedule_preempt_disabled+0xa/0x10 > [ 363.570446] __mutex_lock.isra.9+0x260/0x4f0 > [ 363.570472] ? ath11k_regd_update+0x1f2/0x250 [ath11k] > [ 363.570494] ath11k_regd_update+0x1f2/0x250 [ath11k] > [ 363.570504] process_one_work+0x16c/0x3f0 > [ 363.570510] worker_thread+0x4c/0x440 > [ 363.570516] ? rescuer_thread+0x350/0x350 > [ 363.570521] kthread+0xf8/0x130 > [ 363.570526] ? kthread_unpark+0x70/0x70 > [ 363.570535] ret_from_fork+0x35/0x40 > > Thread A > [ 363.570987] INFO: task gsd-rfkill:1517 blocked for more than 120 seconds. > [ 363.570991] Tainted: G W 5.7.0-rc7-wt-ath+ #3 > [ 363.570994] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 363.570996] gsd-rfkill D 0 1517 1149 0x00004000 > [ 363.571001] Call Trace: > [ 363.571009] __schedule+0x44e/0x6f0 > [ 363.571016] schedule+0x4a/0xb0 > [ 363.571022] schedule_timeout+0x1dd/0x2f0 > [ 363.571033] ? dev_printk+0x56/0x72 > [ 363.571041] wait_for_completion+0x95/0x100 > [ 363.571048] flush_workqueue+0x126/0x3d0 > [ 363.571117] ? ieee80211_stop_device+0x37/0x40 [mac80211] > [ 363.571168] ieee80211_stop_device+0x37/0x40 [mac80211] > [ 363.571215] ieee80211_do_stop+0x549/0x850 [mac80211] > [ 363.571261] ieee80211_stop+0x16/0x20 [mac80211] > [ 363.571268] __dev_close_many+0x9e/0x110 > [ 363.571274] dev_close_many+0x81/0x130 > [ 363.571281] dev_close.part.104+0x3e/0x70 > [ 363.571334] cfg80211_shutdown_all_interfaces+0x43/0xd0 [cfg80211] > [ 363.571373] cfg80211_rfkill_set_block+0x22/0x30 [cfg80211] > [ 363.571380] rfkill_set_block+0x93/0x150 > [ 363.571387] rfkill_fop_write+0x102/0x1a0 > [ 363.571393] vfs_write+0xb3/0x1b0 > [ 363.571399] ksys_write+0xc2/0xe0 > [ 363.571408] ? __x64_sys_poll+0xe9/0x130 > [ 363.571415] do_syscall_64+0x52/0x1e0 > [ 363.571422] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Type 2: > It is same with type 1, thread A's ieee80211_do_stop of mac80211 flush > scan_work which is queued in workqueue of mac80211, but it not start > run because ath11k_regd_update is running in the same workqueue and it > is waiting rtnl_mutex which acquired by thread A, so deadlock happened. > > Thread A > [ 253.749270] INFO: task NetworkManager:1210 blocked for more than 120 seconds. > [ 253.749273] Tainted: G W 5.7.0-rc7-wt-ath+ #3 > [ 253.749274] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 253.749275] NetworkManager D 0 1210 1 0x00004004 > [ 253.749278] Call Trace: > [ 253.749281] __schedule+0x44e/0x6f0 > [ 253.749284] ? enqueue_entity+0xff/0x610 > [ 253.749286] schedule+0x4a/0xb0 > [ 253.749289] schedule_timeout+0x1dd/0x2f0 > [ 253.749292] ? check_preempt_curr+0x50/0x90 > [ 253.749294] ? ttwu_do_wakeup+0x19/0x150 > [ 253.749297] wait_for_completion+0x95/0x100 > [ 253.749300] __flush_work+0x126/0x1d0 > [ 253.749302] ? worker_detach_from_pool+0xa0/0xa0 > [ 253.749332] ieee80211_do_stop+0x831/0x850 [mac80211] > [ 253.749358] ieee80211_stop+0x16/0x20 [mac80211] > [ 253.749361] __dev_close_many+0x9e/0x110 > [ 253.749364] __dev_change_flags+0xc1/0x1c0 > [ 253.749368] dev_change_flags+0x23/0x60 > [ 253.749370] do_setlink+0x373/0xe70 > [ 253.749377] ? __nla_validate_parse.part.6+0x53/0x970 > [ 253.749379] ? cpumask_next+0x16/0x20 > [ 253.749384] ? __snmp6_fill_stats64.isra.47+0x68/0x110 > [ 253.749387] __rtnl_newlink+0x553/0x860 > [ 253.749391] ? __nla_reserve+0x38/0x50 > [ 253.749393] ? __nla_put+0xc/0x20 > [ 253.749396] ? nla_put+0x2f/0x40 > [ 253.749400] ? __kmalloc_node_track_caller+0x58/0x300 > [ 253.749402] ? __nla_reserve+0x38/0x50 > [ 253.749406] ? __kmalloc_reserve.isra.55+0x2e/0x80 > [ 253.749410] ? security_sock_rcv_skb+0x34/0x50 > [ 253.749412] ? sk_filter_trim_cap+0x41/0x1f0 > [ 253.749416] ? netlink_attachskb+0x1ac/0x210 > [ 253.749418] ? skb_queue_tail+0x1b/0x50 > [ 253.749423] ? _cond_resched+0x16/0x40 > [ 253.749427] ? kmem_cache_alloc_trace+0x1ab/0x230 > [ 253.749430] rtnl_newlink+0x43/0x60 > [ 253.749432] rtnetlink_rcv_msg+0x289/0x340 > [ 253.749436] ? __wake_up_common+0x8c/0x130 > [ 253.749438] ? _cond_resched+0x16/0x40 > [ 253.749440] ? __kmalloc_node_track_caller+0x58/0x300 > [ 253.749442] ? rtnl_calcit.isra.33+0x120/0x120 > [ 253.749444] netlink_rcv_skb+0xd1/0x110 > [ 253.749447] netlink_unicast+0x203/0x310 > [ 253.749449] netlink_sendmsg+0x30f/0x450 > [ 253.749455] sock_sendmsg+0x5b/0x60 > [ 253.749458] ____sys_sendmsg+0x219/0x240 > [ 253.749461] ? copy_msghdr_from_user+0x5c/0x90 > [ 253.749463] ? enqueue_task_fair+0xa2/0x570 > [ 253.749465] ___sys_sendmsg+0x88/0xd0 > [ 253.749470] ? futex_wake+0x78/0x160 > [ 253.749473] ? do_futex+0x4fe/0xb80 > [ 253.749476] ? __wake_up_common+0x8c/0x130 > [ 253.749478] ? __sys_sendmsg+0x63/0xa0 > [ 253.749480] __sys_sendmsg+0x63/0xa0 > [ 253.749484] ? ksys_write+0x81/0xe0 > [ 253.749489] do_syscall_64+0x52/0x1e0 > [ 253.749492] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > workqueue of ath11k_regd_update > [ 253.749849] INFO: task kworker/u32:26:5833 blocked for more than 120 seconds. > [ 253.749850] Tainted: G W 5.7.0-rc7-wt-ath+ #3 > [ 253.749851] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 253.749853] kworker/u32:26 D 0 5833 2 0x80004000 > [ 253.749869] Workqueue: phy0 ath11k_regd_update_work [ath11k] > [ 253.749870] Call Trace: > [ 253.749873] __schedule+0x44e/0x6f0 > [ 253.749875] ? __switch_to_asm+0x40/0x70 > [ 253.749878] schedule+0x4a/0xb0 > [ 253.749880] schedule_preempt_disabled+0xa/0x10 > [ 253.749882] __mutex_lock.isra.9+0x260/0x4f0 > [ 253.749884] ? __switch_to_asm+0x40/0x70 > [ 253.749887] ? __switch_to_asm+0x34/0x70 > [ 253.749889] ? __switch_to_asm+0x34/0x70 > [ 253.749892] ? __switch_to_asm+0x40/0x70 > [ 253.749902] ? ath11k_regd_update+0x156/0x250 [ath11k] > [ 253.749912] ath11k_regd_update+0x156/0x250 [ath11k] > [ 253.749915] process_one_work+0x16c/0x3f0 > [ 253.749918] worker_thread+0x4c/0x440 > [ 253.749920] ? rescuer_thread+0x350/0x350 > [ 253.749922] kthread+0xf8/0x130 > [ 253.749923] ? kthread_unpark+0x70/0x70 > [ 253.749926] ret_from_fork+0x22/0x40 > > Type 3: > rtnetlink_rcv_msg of thread C acquired rtnl_mutex and then arrive to > ath11k_debug_get_fw_stats of ath11k, it then acquire the conf_mutex of > ath11k, but is already acquired by thread B which is doing reset by > ath11k_core_halt, then it cancel work of regd_update_work which is > running in thread A, but thread A is sleep because the rtnl_mutex is > acquired by thread C, so deadlock happened. It is thred A wait thread C > release lock, meanwhile thread C wait thread B release lock, and thread > B wait thread A. > > Thread A workqueue of ath11k_regd_update > [ 3021.881737] INFO: task kworker/u16:4:264 blocked for more than 120 seconds. > [ 3021.881739] Tainted: G W 5.7.0-rc7-wt-ath+ #3 > [ 3021.881740] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 3021.881741] kworker/u16:4 D 0 264 2 0x80004000 > [ 3021.881750] Workqueue: phy0 ath11k_regd_update_work [ath11k] > [ 3021.881752] Call Trace: > [ 3021.881756] __schedule+0x44e/0x6f0 > [ 3021.881758] ? __switch_to_asm+0x40/0x70 > [ 3021.881759] schedule+0x4a/0xb0 > [ 3021.881761] schedule_preempt_disabled+0xa/0x10 > [ 3021.881763] __mutex_lock.isra.9+0x260/0x4f0 > [ 3021.881764] ? __switch_to_asm+0x40/0x70 > [ 3021.881766] ? __switch_to_asm+0x34/0x70 > [ 3021.881767] ? __switch_to_asm+0x34/0x70 > [ 3021.881768] ? __switch_to_asm+0x40/0x70 > [ 3021.881774] ? ath11k_regd_update+0x156/0x250 [ath11k] > [ 3021.881779] ath11k_regd_update+0x156/0x250 [ath11k] > [ 3021.881781] process_one_work+0x16c/0x3f0 > [ 3021.881783] worker_thread+0x4c/0x440 > [ 3021.881784] ? rescuer_thread+0x350/0x350 > [ 3021.881785] kthread+0xf8/0x130 > [ 3021.881787] ? kthread_unpark+0x70/0x70 > [ 3021.881788] ret_from_fork+0x35/0x40 > > Thread B > [ 3021.881937] INFO: task kworker/u16:5:2513 blocked for more than 120 seconds. > [ 3021.881938] Tainted: G W 5.7.0-rc7-wt-ath+ #3 > [ 3021.881938] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 3021.881939] kworker/u16:5 D 0 2513 2 0x80004000 > [ 3021.881945] Workqueue: ath11k_wq ath11k_core_restart [ath11k] > [ 3021.881945] Call Trace: > [ 3021.881947] __schedule+0x44e/0x6f0 > [ 3021.881949] ? enqueue_entity+0xff/0x610 > [ 3021.881950] schedule+0x4a/0xb0 > [ 3021.881951] schedule_timeout+0x1dd/0x2f0 > [ 3021.881953] ? check_preempt_curr+0x50/0x90 > [ 3021.881954] ? ttwu_do_wakeup+0x19/0x150 > [ 3021.881956] wait_for_completion+0x95/0x100 > [ 3021.881957] __flush_work+0x126/0x1d0 > [ 3021.881958] ? worker_detach_from_pool+0xa0/0xa0 > [ 3021.881960] __cancel_work_timer+0x10c/0x190 > [ 3021.881962] ? put_cpu_partial+0x99/0x100 > [ 3021.881966] ath11k_core_halt+0x57/0xe0 [ath11k] > [ 3021.881970] ath11k_core_restart+0x2ca/0x390 [ath11k] > [ 3021.881971] process_one_work+0x16c/0x3f0 > [ 3021.881972] worker_thread+0x4c/0x440 > [ 3021.881974] ? rescuer_thread+0x350/0x350 > [ 3021.881975] kthread+0xf8/0x130 > [ 3021.881976] ? kthread_unpark+0x70/0x70 > [ 3021.881977] ret_from_fork+0x35/0x40 > > Thread C: > [ 3021.881795] INFO: task NetworkManager:898 blocked for more than 120 seconds. > [ 3021.881796] Tainted: G W 5.7.0-rc7-wt-ath+ #3 > [ 3021.881797] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 3021.881798] NetworkManager D 0 898 1 0x00004000 > [ 3021.881799] Call Trace: > [ 3021.881800] __schedule+0x44e/0x6f0 > [ 3021.881802] ? __switch_to_asm+0x40/0x70 > [ 3021.881803] schedule+0x4a/0xb0 > [ 3021.881804] schedule_preempt_disabled+0xa/0x10 > [ 3021.881806] __mutex_lock.isra.9+0x260/0x4f0 > [ 3021.881811] ? ath11k_debug_get_fw_stats+0x4b/0xf0 [ath11k] > [ 3021.881816] ath11k_debug_get_fw_stats+0x4b/0xf0 [ath11k] > [ 3021.881821] ath11k_mac_op_sta_statistics+0x184/0x1a0 [ath11k] > [ 3021.881836] sta_set_sinfo+0xab/0xb30 [mac80211] > [ 3021.881849] ieee80211_get_station+0x50/0x70 [mac80211] > [ 3021.881867] nl80211_get_station+0x8e/0x250 [cfg80211] > [ 3021.881870] genl_rcv_msg+0x1e5/0x420 > [ 3021.881873] ? __rtnl_unlock+0x25/0x50 > [ 3021.881875] ? netdev_run_todo+0x5d/0x2d0 > [ 3021.881876] ? genl_family_rcv_msg_attrs_parse+0x120/0x120 > [ 3021.881878] netlink_rcv_skb+0xd1/0x110 > [ 3021.881879] genl_rcv+0x24/0x40 > [ 3021.881880] netlink_unicast+0x203/0x310 > [ 3021.881882] netlink_sendmsg+0x30f/0x450 > [ 3021.881884] sock_sendmsg+0x5b/0x60 > [ 3021.881886] ____sys_sendmsg+0x219/0x240 > [ 3021.881887] ? copy_msghdr_from_user+0x5c/0x90 > [ 3021.881888] ? ____sys_recvmsg+0xa7/0x1a0 > [ 3021.881890] ___sys_sendmsg+0x88/0xd0 > [ 3021.881891] ? copy_msghdr_from_user+0x5c/0x90 > [ 3021.881892] ? ___sys_recvmsg+0x9e/0xd0 > [ 3021.881895] ? poll_select_finish+0x210/0x210 > [ 3021.881897] ? ep_poll+0x2da/0x430 > [ 3021.881898] ? poll_select_finish+0x210/0x210 > [ 3021.881899] ? __sys_sendmsg+0x63/0xa0 > [ 3021.881900] __sys_sendmsg+0x63/0xa0 > [ 3021.881902] ? do_epoll_wait+0x83/0xc0 > [ 3021.881904] do_syscall_64+0x52/0x1e0 > [ 3021.881906] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > This patch add max wait for 3 seconds for the rtnl_mutex, if not > acquire untill 3 seconds, then return fail. Then it not happen > "blocked for more than 120 seconds" with this patch after do > simulate test with command:"iw reg set;ifconfig wlan down > > This patch also add cond_resched while rtnl_trylock to avoid > synchronize_rcu wait. > > It is very easy to happen synchronize_rcu wait ATH11K_MAX_REG_WAIT > which is 3 seconds without add cond_resched. > > Test steps: > 1. rmmod ath11k_pci > 2. insmod ath11k_pci > 3. dmesg show log: ath11k_pci 0000:05:00.0: rtnl acquire failed > > The reason is because when insmod ath11k_pci, wlan is up, then thread A > systemd-udevd acquired rtnl_mutex and call dev_change_name with below > call stack but meanwhile ath11k_regd_update is called from function > __ath11k_mac_register of thread B. Function rtnl_trylock thread B > failed every time untill ATH11K_MAX_REG_WAIT which is 3 seconds, because > rtnl_mutex is acquired by thread A before, meanwhile, dev_change_name > of thread A called to synchronize_rcu, and it entered to sleep state > untill thread B exit rtnl_trylock, it is same time of ATH11K_MAX_REG_WAIT > which is 3 seconds, after 3 seconds, ath11k_regd_update of thread B > return with fail and lead __ath11k_mac_register fail, and function > synchronize_rcu of thread A return. > > The wait of synchronize_rcu is because only CONFIG_PREEMPT_VOLUNTARY is > enabled(not enabled PREEMPT and PREEMPT_RT), it lead schedule only > happened when voluntarily preempt. Thread B called rtnl_trylock in > loop untill 3 seconds, it not happened voluntarily preempt and no > schedule in the 3 seconds, and synchronize_rcu need wait schedule > happened on all cpus. Schedule on the cpu of thread B happened 3 > seconds later, it lead synchronize_rcu wait 3 seconds for thread B, > then synchronize_rcu returned. > > Call stack of thread A > [ 5158.606564] task:systemd-udevd state:D stack: 0 pid: 3359 ppid: 283 flags:0x00004000 > [ 5158.606570] Call Trace: > [ 5158.606585] __schedule+0x2d0/0x7e0 > [ 5158.606594] schedule+0x46/0xb0 > [ 5158.606599] schedule_timeout+0x206/0x2b0 > [ 5158.606605] ? kfree+0xae/0x210 > [ 5158.606609] wait_for_completion+0x85/0xe0 > [ 5158.606615] __wait_rcu_gp+0xfc/0x130 > [ 5158.606624] synchronize_rcu+0x3e/0x50 > [ 5158.606629] ? invoke_rcu_core+0x90/0x90 > [ 5158.606632] ? __bpf_trace_rcu_utilization+0x10/0x10 > [ 5158.606636] dev_change_name+0x1c9/0x2e0 > [ 5158.606643] do_setlink+0xc18/0xfc0 > [ 5158.606649] ? __nla_validate_parse.part.7+0x44/0xaf0 > [ 5158.606654] rtnl_setlink+0x107/0x160 > [ 5158.606669] rtnetlink_rcv_msg+0x130/0x350 > [ 5158.606674] ? mntput_no_expire+0x35/0x220 > [ 5158.606679] ? _cond_resched+0x16/0x40 > [ 5158.606684] ? rtnl_calcit.isra.36+0x100/0x100 > [ 5158.606691] netlink_rcv_skb+0xb9/0xf0 > [ 5158.606698] netlink_unicast+0x16a/0x270 > [ 5158.606703] netlink_sendmsg+0x2e4/0x420 > [ 5158.606709] sock_sendmsg+0x5b/0x60 > [ 5158.606713] __sys_sendto+0xd8/0x150 > [ 5158.606723] ? aa_sk_perm+0x3e/0x1f0 > [ 5158.606728] ? netlink_getsockopt+0x1bf/0x250 > [ 5158.606734] ? exit_to_user_mode_prepare+0x38/0x130 > [ 5158.606738] __x64_sys_sendto+0x24/0x30 > [ 5158.606744] do_syscall_64+0x33/0x80 > [ 5158.606750] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > [ 5158.606755] RIP: 0033:0x7f5a188f5ab3 > [ 5158.606757] Code: Unable to access opcode bytes at RIP 0x7f5a188f5a89. > [ 5158.606760] RSP: 002b:00007ffde036f398 EFLAGS: 00000246 ORIG_RAX: 000000000000002c > [ 5158.606763] RAX: ffffffffffffffda RBX: 0000560825157800 RCX: 00007f5a188f5ab3 > [ 5158.606765] RDX: 000000000000002c RSI: 0000560825130c90 RDI: 000000000000000f > [ 5158.606767] RBP: 0000000000000d1f R08: 00007ffde036f450 R09: 0000000000000010 > [ 5158.606769] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006 > [ 5158.606771] R13: 0000560825130b80 R14: 000000000000000e R15: 0000560825144800 > [ 5158.606777] ath11k_pci 0000:05:00.0: rtnl acquire failed > > Below is time cost of synchronize_rcu called from dev_change_name. > It is 3 seconds from dev_change_name_L67 to dev_change_name_L69, this > is time cost of synchronize_rcu in dev_change_name. > log: > systemd-udevd 3109 [003] 545.393423: probe:dev_change_name_L65: (ffffffffbb891b84) > systemd-udevd 3109 [003] 545.393452: probe:dev_change_name_L65: (ffffffffbb891b8f) > [ 545.393339] ath11k_pci 0000:05:00.0 wls1: renamed from wlan0 > systemd-udevd 3109 [003] 545.393470: probe:dev_change_name_L67: (ffffffffbb891b94) > [ 548.398407] ath11k_pci 0000:05:00.0: rtnl acquire failed > systemd-udevd 3109 [000] 548.406522: probe:dev_change_name_L69: (ffffffffbb891b99) > > After add cond_resched, the wait of 3 seconds by synchronize_rcu disappeared. > log: > systemd-udevd 3834 [001] 1918.635387: probe:dev_change_name_L65: (ffffffffbb891b84) > systemd-udevd 3834 [001] 1918.635391: probe:dev_change_name_L65: (ffffffffbb891b8f) > systemd-udevd 3834 [001] 1918.635395: probe:dev_change_name_L67: (ffffffffbb891b94) > systemd-udevd 3834 [000] 1918.662665: probe:dev_change_name_L69: (ffffffffbb891b99) > > It also fix deadlock below. > Thread A hold the rtnl lock by wiphy_suspend() and wait at > cancel_work_sync(&ar->regd_update_work) in ath11k_mac_op_stop(). > [ffffb5ef835a7b20] __schedule at ffffffff8cb10860 > [ffffb5ef835a7ba8] schedule at ffffffff8cb10f24 > [ffffb5ef835a7bb8] schedule_timeout at ffffffff8cb16d88 > [ffffb5ef835a7c30] wait_for_completion at ffffffff8cb11778 > [ffffb5ef835a7c78] __flush_work at ffffffff8c0b30cd > [ffffb5ef835a7cf0] __cancel_work_timer at ffffffff8c0b33ad > [ffffb5ef835a7d60] ath11k_mac_op_stop at ffffffffc19fe40f [ath11k] > [ffffb5ef835a7d98] drv_stop at ffffffffc18cb240 [mac80211] > [ffffb5ef835a7da8] __ieee80211_suspend at ffffffffc194accc [mac80211] > [ffffb5ef835a7dd8] wiphy_suspend at ffffffffc17d01ac [cfg80211] > [ffffb5ef835a7e08] dpm_run_callback at ffffffff8c75118a > [ffffb5ef835a7e38] __device_suspend at ffffffff8c751630 > [ffffb5ef835a7e70] async_suspend at ffffffff8c7519ea > [ffffb5ef835a7e88] async_run_entry_fn at ffffffff8c0bf4ce > [ffffb5ef835a7ea8] process_one_work at ffffffff8c0b1a24 > [ffffb5ef835a7ee0] worker_thread at ffffffff8c0b1c4a > [ffffb5ef835a7f18] kthread at ffffffff8c0b9cb8 > [ffffb5ef835a7f50] ret_from_fork at ffffffff8c001d32 > > Thread B wait the rtnl lock which hold by Thread A in > ath11k_regd_update(). > [ffffb5ef8333fd58] __schedule at ffffffff8cb10860 > [ffffb5ef8333fde0] schedule at ffffffff8cb10f24 > [ffffb5ef8333fdf0] schedule_preempt_disabled at ffffffff8cb112b4 > [ffffb5ef8333fdf8] __mutex_lock at ffffffff8cb127ea > [ffffb5ef8333fe78] ath11k_regd_update at ffffffffc1a07757 [ath11k] > [ffffb5ef8333fea8] process_one_work at ffffffff8c0b1a24 > [ffffb5ef8333fee0] worker_thread at ffffffff8c0b1c4a > [ffffb5ef8333ff18] kthread at ffffffff8c0b9cb8 > [ffffb5ef8333ff50] ret_from_fork at ffffffff8c001d32 > > Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3 > > Signed-off-by: Wen Gong <quic_wgong@xxxxxxxxxxx> There's now also a bug report about this problem: https://bugzilla.kernel.org/show_bug.cgi?id=216434 Patch set to RFC. -- https://patchwork.kernel.org/project/linux-wireless/patch/20220701072855.13655-1-quic_wgong@xxxxxxxxxxx/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
