Following commit a05829a7222e ("cfg80211: avoid holding the RTNL when
calling the driver"), the mwifiex_pcie module fails to unload. This also
prevents the device from rebooting / shutting down.
Attempting to unload the module produces the log pasted below. Upon
further investigation, this looks like a deadlock inside
_cfg80211_unregister_wdev():
- According to [1], this function expects the rdev->wiphy.mtx to be
held.
- Down the line, this function (through some indirections, see third
trace in log below) calls call_netdevice_notifiers(NETDEV_GOING_DOWN,
...) [2].
- One of the registered notifiers seems to be
cfg80211_netdev_notifier_call(), which attempts to lock
rdev->wiphy.mtx again [3], completing the deadlock.
Regards,
Max
[1]: https://elixir.bootlin.com/linux/v5.13-rc1/source/net/wireless/core.c#L1130
[2]: https://elixir.bootlin.com/linux/v5.13-rc1/source/net/core/dev.c#L1667
[3]: https://elixir.bootlin.com/linux/v5.13-rc1/source/net/wireless/core.c#L1428
[ 245.504760] INFO: task kworker/u16:1:107 blocked for more than 122 seconds.
[ 245.504764] Tainted: G C OE 5.11.0-1-surface-dev #2
[ 245.504765] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 245.504766] task:kworker/u16:1 state:D stack: 0 pid: 107 ppid: 2 flags:0x00004000
[ 245.504771] Workqueue: events_power_efficient reg_check_chans_work [cfg80211]
[ 245.504817] Call Trace:
[ 245.504820] __schedule+0x2dd/0x8b0
[ 245.504826] schedule+0x5b/0xc0
[ 245.504829] schedule_preempt_disabled+0x11/0x20
[ 245.504831] __mutex_lock.constprop.0+0x317/0x500
[ 245.504835] reg_check_chans_work+0x2d/0x3c0 [cfg80211]
[ 245.504867] process_one_work+0x214/0x3e0
[ 245.504870] worker_thread+0x4d/0x3d0
[ 245.504872] ? rescuer_thread+0x410/0x410
[ 245.504874] kthread+0x133/0x150
[ 245.504877] ? __kthread_bind_mask+0x60/0x60
[ 245.504880] ret_from_fork+0x22/0x30
[ 245.504900] INFO: task wpa_supplicant:903 blocked for more than 122 seconds.
[ 245.504901] Tainted: G C OE 5.11.0-1-surface-dev #2
[ 245.504902] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 245.504903] task:wpa_supplicant state:D stack: 0 pid: 903 ppid: 1 flags:0x00000000
[ 245.504906] Call Trace:
[ 245.504907] __schedule+0x2dd/0x8b0
[ 245.504910] schedule+0x5b/0xc0
[ 245.504912] schedule_preempt_disabled+0x11/0x20
[ 245.504914] __mutex_lock.constprop.0+0x317/0x500
[ 245.504917] nl80211_pre_doit+0x16/0x130 [cfg80211]
[ 245.504951] genl_family_rcv_msg_doit+0xe7/0x160
[ 245.504956] genl_rcv_msg+0xef/0x1e0
[ 245.504959] ? nl80211_send_scan_start+0x90/0x90 [cfg80211]
[ 245.504993] ? genl_get_cmd+0xd0/0xd0
[ 245.504996] netlink_rcv_skb+0x5b/0x100
[ 245.504999] genl_rcv+0x24/0x40
[ 245.505002] netlink_unicast+0x242/0x340
[ 245.505004] netlink_sendmsg+0x243/0x480
[ 245.505007] sock_sendmsg+0x5e/0x60
[ 245.505011] ____sys_sendmsg+0x25a/0x2a0
[ 245.505013] ? copy_msghdr_from_user+0x6e/0xa0
[ 245.505017] ___sys_sendmsg+0x97/0xe0
[ 245.505022] __sys_sendmsg+0x81/0xd0
[ 245.505025] do_syscall_64+0x33/0x40
[ 245.505028] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 245.505032] RIP: 0033:0x7fa6606cd737
[ 245.505034] RSP: 002b:00007ffddff52178 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 245.505036] RAX: ffffffffffffffda RBX: 0000559697c3e780 RCX: 00007fa6606cd737
[ 245.505038] RDX: 0000000000000000 RSI: 00007ffddff521b0 RDI: 0000000000000006
[ 245.505039] RBP: 0000559697c3e690 R08: 0000000000000004 R09: 00007fa66078ea60
[ 245.505040] R10: 00007ffddff52284 R11: 0000000000000246 R12: 0000559697c7a9a0
[ 245.505042] R13: 00007ffddff521b0 R14: 00007ffddff52284 R15: 0000559697c71100
[ 245.505072] INFO: task modprobe:1930 blocked for more than 122 seconds.
[ 245.505073] Tainted: G C OE 5.11.0-1-surface-dev #2
[ 245.505074] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 245.505075] task:modprobe state:D stack: 0 pid: 1930 ppid: 1879 flags:0x00004004
[ 245.505078] Call Trace:
[ 245.505079] __schedule+0x2dd/0x8b0
[ 245.505082] schedule+0x5b/0xc0
[ 245.505084] schedule_preempt_disabled+0x11/0x20
[ 245.505086] __mutex_lock.constprop.0+0x317/0x500
[ 245.505088] ? vprintk_emit+0x13a/0x270
[ 245.505093] cfg80211_netdev_notifier_call+0x12a/0x4e0 [cfg80211]
[ 245.505125] raw_notifier_call_chain+0x44/0x60
[ 245.505127] __dev_close_many+0x6b/0x120
[ 245.505130] dev_close_many+0x92/0x140
[ 245.505132] unregister_netdevice_many+0x150/0x6f0
[ 245.505135] unregister_netdevice_queue+0x96/0xd0
[ 245.505138] _cfg80211_unregister_wdev+0x135/0x1d0 [cfg80211]
[ 245.505167] mwifiex_del_virtual_intf+0x178/0x1a0 [mwifiex]
[ 245.505181] mwifiex_uninit_sw+0x1cf/0x1f0 [mwifiex]
[ 245.505188] mwifiex_remove_card+0x7b/0x80 [mwifiex]
[ 245.505196] pci_device_remove+0x3b/0xa0
[ 245.505200] __device_release_driver+0x17a/0x230
[ 245.505204] driver_detach+0xc9/0x110
[ 245.505206] bus_remove_driver+0x58/0xd0
[ 245.505208] pci_unregister_driver+0x3b/0x90
[ 245.505211] __do_sys_delete_module+0x19e/0x2a0
[ 245.505216] do_syscall_64+0x33/0x40
[ 245.505218] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 245.505221] RIP: 0033:0x7fd803e30cab
[ 245.505223] RSP: 002b:00007fffa7589d58 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
[ 245.505224] RAX: ffffffffffffffda RBX: 0000559b9ae6ce80 RCX: 00007fd803e30cab
[ 245.505226] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 0000559b9ae6cee8
[ 245.505227] RBP: 0000559b9ae6ce80 R08: 0000000000000000 R09: 0000000000000000
[ 245.505228] R10: 00007fd803ea4ac0 R11: 0000000000000206 R12: 0000559b9ae6cee8
[ 245.505229] R13: 0000000000000000 R14: 0000000000000000 R15: 0000559b9ae6c5d0
