[FS#473] ath9k unstable - kernel panic every ~5 minutes

[LEDE Bugs]

The following task has a new comment added:

FS#473 - ath9k unstable - kernel panic every ~5 minutes
User who did this - Nick Lowe (nick_lowe)

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Crash from Kernel 4.9.8 below.

LEDE Reboot SNAPSHOT r3386-0799de6 / LuCI Master (git-17.041.67116-1834eff)

Yes, I do suspect that the airtime fairness patches are not SMP safe.

I tried booting adding nocpu or maxcpus=0 to grub but this will not
boot. Would I have to use a build without SMP support? Is there
another suggested method for achieving this?

Thanks,

Nick

root at LEDE:/# [  345.305712] BUG: unable to handle kernel paging request at 0000000000015970
[  345.312786] IP: [] native_queued_spin_lock_slowpath+0x120/0x16c
[  345.320361] PGD 11940a067 [  345.322908] PUD 11861f067 
PMD 0 [  345.326210] 
[  345.327752] Oops: 0002 [#1] SMP
[  345.330939] Modules linked in: ath9k ath9k_common pppoe ppp_async ath9k_hw ath pppox ppp_generic nf_conntrack_
ipv6 mac80211 iptable_nat ipt_REJECT ipt_MASQUERADE cfg80211 xt_time xt_tcpudp xt_state xt_nat xt_multiport xt_ma
rk xt_mac xt_limit xt_conntrack xt_comment xt_TCPMSS xt_REDIRECT xt_LOG xt_CT slhc r8169 nf_reject_ipv4 nf_nat_re
direct nf_nat_masquerade_ipv4 nf_conntrack_ipv4 nf_nat_ipv4 nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_c
onntrack_rtcache nf_conntrack iptable_mangle iptable_filter ip_tables e1000e crc_ccitt compat i2c_dev ip6t_REJECT
 nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables x_tables igb i2c_algo_bit i2
c_core e1000 button_hotplug ptp pps_core mii
[  345.395633] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.9.8 #0
[  345.401495] Hardware name: PC Engines apu2/apu2, BIOS 6f1e98a-dirty 05/15/2016
[  345.408767] task: ffff88011a0e0b40 task.stack: ffffc90000070000
[  345.414716] RIP: 0010:[]  [] native_queued_spin_lock_slowpath+0x120/0x16c
[  345.424722] RSP: 0018:ffff88011ed83d88  EFLAGS: 00010202
[  345.430063] RAX: 000000000000060e RBX: ffff880118f9a0f8 RCX: 0000000000015970
[  345.437226] RDX: ffff88011ed95940 RSI: 0000000000100000 RDI: ffff880118edb4d0
[  345.444393] RBP: ffff88011ed83e70 R08: 0000000000000001 R09: 0000000000000000
[  345.451554] R10: ffffc9000140be28 R11: ffff8801196921c0 R12: ffff880118e04820
[  345.458739] R13: ffff88011ed83ec0 R14: ffff880118ecfb00 R15: ffff880118ed9c20
[  345.465920] FS:  0000000000000000(0000) GS:ffff88011ed80000(0000) knlGS:0000000000000000
[  345.474059] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  345.479834] CR2: 0000000000015970 CR3: 0000000118a39000 CR4: 00000000000406e0
[  345.486994] Stack:
[  345.489037]  ffffffff8143a9af ffffffffa0286c95 0000000000000000 0000000000000000
[  345.496574]  0000000000000000 0000000000000000 0000000000000400 ffff88011ed83ea0
[  345.504122]  ffffffff00000001 ffff880118edb4b0 0000000000000000 ffff880118ed8de0
[  345.511673] Call Trace:
[  345.514157]   [  345.516107]  [] ? _raw_spin_lock_bh+0x21/0x24
[  345.522111]  [] ? ath_tx_aggr_wakeup+0x1ed/0xafa [ath9k]
[  345.529041]  [] ? load_balance+0x14e/0x6f8
[  345.534745]  [] ? ath_tx_edma_tasklet+0x2d0/0x2f8 [ath9k]
[  345.541751]  [] ? ath9k_tasklet+0x178/0x1d1 [ath9k]
[  345.548234]  [] ? tasklet_action+0x9f/0xa8
[  345.553930]  [] ? __do_softirq+0xb8/0x1a1
[  345.559540]  [] ? irq_exit+0x4f/0x5b
[  345.564715]  [] ? do_IRQ+0xa4/0xba
[  345.569722]  [] ? common_interrupt+0x7f/0x7f
[  345.575583]   [  345.577532]  [] ? cpuidle_enter_state+0x134/0x189
[  345.583862]  [] ? cpuidle_enter_state+0xed/0x189
[  345.590074]  [] ? cpu_startup_entry+0x156/0x1c9
[  345.596206]  [] ? start_secondary+0x12b/0x12e
[  345.602163] Code: e8 10 66 87 47 02 c1 e0 10 74 67 48 89 c1 c1 e8 12 48 c1 e9 0c ff c8 83 e1 30 48 98 48 81 c1
 40 59 01 00 48 03 0c c5 60 82 77 81  89 11 8b 42 08 85 c0 75 04 f3 90 eb f5 48 8b 0a 48 85 c9 74 
[  345.622747] RIP  [] native_queued_spin_lock_slowpath+0x120/0x16c
[  345.630404]  RSP 
[  345.633923] CR2: 0000000000015970
[  345.637273] ---[ end trace 4ad31ac2f976a764 ]---
[  345.641923] Kernel panic - not syncing: Fatal exception in interrupt
[  345.648342] Kernel Offset: disabled
[  345.651864] Rebooting in 3 seconds..[  348.658078] ACPI MEMORY or I/O RESET_REG.
PCEngines apu2
coreboot build 20160515
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=473#comment1740