hostapd hangs after "nl80211: Set beacon (beacon_set=0)"

[Jue]

Hi Ben,

thank you for your reply!

> Sounds like the kernel locked up somehow.
> 
> Can you use sysrq to dump tasks and/or locks or something?

Call stack of blocked tasks (hostapd shows up ...):
> [ 6834.585242] SysRq : Show Blocked State
> [ 6834.594603]   task                PC stack   pid father
> [ 6834.594648] ifplugd         D c037a204     0  1537      1 0x00000000
> [ 6834.594721] [<c037a204>] (__schedule+0x2bc/0x568) from [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154)
> [ 6834.594761] [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154) from [<c02d80bc>] (dev_ioctl+0x3e0/0x864)
> [ 6834.594803] [<c02d80bc>] (dev_ioctl+0x3e0/0x864) from [<c00c855c>] (do_vfs_ioctl+0x7c/0x578)
> [ 6834.594835] [<c00c855c>] (do_vfs_ioctl+0x7c/0x578) from [<c00c8a8c>] (sys_ioctl+0x34/0x60)
> [ 6834.594876] [<c00c8a8c>] (sys_ioctl+0x34/0x60) from [<c000d980>] (ret_fast_syscall+0x0/0x30)
> [ 6834.594896] ifplugd         D c037a204     0  1573      1 0x00000000
> [ 6834.594933] [<c037a204>] (__schedule+0x2bc/0x568) from [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154)
> [ 6834.594963] [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154) from [<c02d80bc>] (dev_ioctl+0x3e0/0x864)
> [ 6834.594992] [<c02d80bc>] (dev_ioctl+0x3e0/0x864) from [<c00c855c>] (do_vfs_ioctl+0x7c/0x578)
> [ 6834.595021] [<c00c855c>] (do_vfs_ioctl+0x7c/0x578) from [<c00c8a8c>] (sys_ioctl+0x34/0x60)
> [ 6834.595052] [<c00c8a8c>] (sys_ioctl+0x34/0x60) from [<c000d980>] (ret_fast_syscall+0x0/0x30)
> [ 6834.595071] ntpd            D c037a204     0  2065      1 0x00000001
> [ 6834.595108] [<c037a204>] (__schedule+0x2bc/0x568) from [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154)
> [ 6834.595137] [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154) from [<c02d81c0>] (dev_ioctl+0x4e4/0x864)
> [ 6834.595167] [<c02d81c0>] (dev_ioctl+0x4e4/0x864) from [<c00c855c>] (do_vfs_ioctl+0x7c/0x578)
> [ 6834.595197] [<c00c855c>] (do_vfs_ioctl+0x7c/0x578) from [<c00c8a8c>] (sys_ioctl+0x34/0x60)
> [ 6834.595227] [<c00c8a8c>] (sys_ioctl+0x34/0x60) from [<c000d980>] (ret_fast_syscall+0x0/0x30)
> [ 6834.595281] ifplugd         D c037a204     0 17041      1 0x00000000
> [ 6834.595321] [<c037a204>] (__schedule+0x2bc/0x568) from [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154)
> [ 6834.595351] [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154) from [<c02d80bc>] (dev_ioctl+0x3e0/0x864)
> [ 6834.595381] [<c02d80bc>] (dev_ioctl+0x3e0/0x864) from [<c00c855c>] (do_vfs_ioctl+0x7c/0x578)
> [ 6834.595411] [<c00c855c>] (do_vfs_ioctl+0x7c/0x578) from [<c00c8a8c>] (sys_ioctl+0x34/0x60)
> [ 6834.595442] [<c00c8a8c>] (sys_ioctl+0x34/0x60) from [<c000d980>] (ret_fast_syscall+0x0/0x30)
> [ 6834.595462] kworker/u:2     D c037a204     0 17673      2 0x00000000
> [ 6834.595499] [<c037a204>] (__schedule+0x2bc/0x568) from [<c037ae68>] (schedule_timeout+0x158/0x230)
> [ 6834.595528] [<c037ae68>] (schedule_timeout+0x158/0x230) from [<c037a670>] (wait_for_common+0xcc/0x198)
> [ 6834.595637] [<c037a670>] (wait_for_common+0xcc/0x198) from [<bf101a84>] (ath9k_wmi_cmd+0x174/0x1b4 [ath9k_htc])
> [ 6834.595737] [<bf101a84>] (ath9k_wmi_cmd+0x174/0x1b4 [ath9k_htc]) from [<bf106d2c>] (ath9k_regread+0x38/0x58 [ath9k_htc])
> [ 6834.595834] [<bf106d2c>] (ath9k_regread+0x38/0x58 [ath9k_htc]) from [<bf106ee8>] (ath9k_reg_rmw+0x18/0x38 [ath9k_htc])
> [ 6834.596135] [<bf106ee8>] (ath9k_reg_rmw+0x18/0x38 [ath9k_htc]) from [<bf051148>] (ar9002_hw_pa_cal.part.3+0x250/0x4d8 [ath9k_hw])
> [ 6834.596403] [<bf051148>] (ar9002_hw_pa_cal.part.3+0x250/0x4d8 [ath9k_hw]) from [<bf0514c0>] (ar9002_hw_calibrate+0xf0/0x440 [ath9k_hw])
> [ 6834.596607] [<bf0514c0>] (ar9002_hw_calibrate+0xf0/0x440 [ath9k_hw]) from [<bf105f54>] (ath9k_htc_ani_work+0xe4/0x1d8 [ath9k_htc])
> [ 6834.596698] [<bf105f54>] (ath9k_htc_ani_work+0xe4/0x1d8 [ath9k_htc]) from [<c003da30>] (process_one_work+0x134/0x38c)
> [ 6834.596738] [<c003da30>] (process_one_work+0x134/0x38c) from [<c003e4a4>] (worker_thread+0x1a0/0x354)
> [ 6834.596777] [<c003e4a4>] (worker_thread+0x1a0/0x354) from [<c0042e3c>] (kthread+0x84/0x8c)
> [ 6834.596814] [<c0042e3c>] (kthread+0x84/0x8c) from [<c000e930>] (kernel_thread_exit+0x0/0x8)
> [ 6834.596839] ifplugd         D c037a204     0 18588      1 0x00000000
> [ 6834.596880] [<c037a204>] (__schedule+0x2bc/0x568) from [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154)
> [ 6834.596911] [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154) from [<c02d80bc>] (dev_ioctl+0x3e0/0x864)
> [ 6834.596945] [<c02d80bc>] (dev_ioctl+0x3e0/0x864) from [<c00c855c>] (do_vfs_ioctl+0x7c/0x578)
> [ 6834.596975] [<c00c855c>] (do_vfs_ioctl+0x7c/0x578) from [<c00c8a8c>] (sys_ioctl+0x34/0x60)
> [ 6834.597006] [<c00c8a8c>] (sys_ioctl+0x34/0x60) from [<c000d980>] (ret_fast_syscall+0x0/0x30)
> [ 6834.597024] hostapd         D c037a204     0 18672  17227 0x00000000
> [ 6834.597061] [<c037a204>] (__schedule+0x2bc/0x568) from [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154)
> [ 6834.597125] [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154) from [<bf101990>] (ath9k_wmi_cmd+0x80/0x1b4 [ath9k_htc])
> [ 6834.597217] [<bf101990>] (ath9k_wmi_cmd+0x80/0x1b4 [ath9k_htc]) from [<bf106d2c>] (ath9k_regread+0x38/0x58 [ath9k_htc])
> [ 6834.597390] [<bf106d2c>] (ath9k_regread+0x38/0x58 [ath9k_htc]) from [<bf046a84>] (ath9k_hw_wait+0x58/0x90 [ath9k_hw])
> [ 6834.597611] [<bf046a84>] (ath9k_hw_wait+0x58/0x90 [ath9k_hw]) from [<bf046ae0>] (ath9k_hw_reset_tsf+0x24/0x48 [ath9k_hw])
> [ 6834.597790] [<bf046ae0>] (ath9k_hw_reset_tsf+0x24/0x48 [ath9k_hw]) from [<bf106464>] (ath9k_htc_beacon_config_ap+0x44/0x154 [ath9k_htc])
> [ 6834.597896] [<bf106464>] (ath9k_htc_beacon_config_ap+0x44/0x154 [ath9k_htc]) from [<bf106af8>] (ath9k_htc_beacon_config+0x138/0x160 [ath9k_htc])
> [ 6834.597990] [<bf106af8>] (ath9k_htc_beacon_config+0x138/0x160 [ath9k_htc]) from [<bf105750>] (ath9k_htc_bss_info_changed+0xe8/0x2a8 [ath9k_htc])
> [ 6834.598269] [<bf105750>] (ath9k_htc_bss_info_changed+0xe8/0x2a8 [ath9k_htc]) from [<bf0b30e4>] (ieee80211_bss_info_change_notify+0xa8/0x184 [mac80211])
> [ 6834.598563] [<bf0b30e4>] (ieee80211_bss_info_change_notify+0xa8/0x184 [mac80211]) from [<bf0c66f0>] (ieee80211_config_beacon+0x54/0x1a8 [mac80211])
> [ 6834.598965] [<bf0c66f0>] (ieee80211_config_beacon+0x54/0x1a8 [mac80211]) from [<bf00f608>] (nl80211_addset_beacon+0x160/0x288 [cfg80211])
> [ 6834.599131] [<bf00f608>] (nl80211_addset_beacon+0x160/0x288 [cfg80211]) from [<c02f673c>] (genl_rcv_msg+0x220/0x258)
> [ 6834.599167] [<c02f673c>] (genl_rcv_msg+0x220/0x258) from [<c02f5b40>] (netlink_rcv_skb+0xac/0xc0)
> [ 6834.599197] [<c02f5b40>] (netlink_rcv_skb+0xac/0xc0) from [<c02f6510>] (genl_rcv+0x18/0x24)
> [ 6834.599225] [<c02f6510>] (genl_rcv+0x18/0x24) from [<c02f5520>] (netlink_unicast+0x2b0/0x308)
> [ 6834.599253] [<c02f5520>] (netlink_unicast+0x2b0/0x308) from [<c02f5848>] (netlink_sendmsg+0x230/0x298)
> [ 6834.599288] [<c02f5848>] (netlink_sendmsg+0x230/0x298) from [<c02c2988>] (sock_sendmsg+0x9c/0xbc)
> [ 6834.599320] [<c02c2988>] (sock_sendmsg+0x9c/0xbc) from [<c02c2d70>] (__sys_sendmsg+0x2d4/0x2f0)
> [ 6834.599351] [<c02c2d70>] (__sys_sendmsg+0x2d4/0x2f0) from [<c02c47d8>] (sys_sendmsg+0x3c/0x68)
> [ 6834.599386] [<c02c47d8>] (sys_sendmsg+0x3c/0x68) from [<c000d980>] (ret_fast_syscall+0x0/0x30)
> [ 6834.599406] ifplugd         D c037a204     0 18689      1 0x00000000
> [ 6834.599449] [<c037a204>] (__schedule+0x2bc/0x568) from [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154)
> [ 6834.599483] [<c037b720>] (__mutex_lock_slowpath+0xb8/0x154) from [<c02d80bc>] (dev_ioctl+0x3e0/0x864)
> [ 6834.599517] [<c02d80bc>] (dev_ioctl+0x3e0/0x864) from [<c00c855c>] (do_vfs_ioctl+0x7c/0x578)
> [ 6834.599549] [<c00c855c>] (do_vfs_ioctl+0x7c/0x578) from [<c00c8a8c>] (sys_ioctl+0x34/0x60)
> [ 6834.599578] [<c00c8a8c>] (sys_ioctl+0x34/0x60) from [<c000d980>] (ret_fast_syscall+0x0/0x30)

Thanks,
Jue