[FS#764] MT7621: Any traffic shaping results in crashes/stack traces

[LEDE Bugs]

The following task has a new comment added:

FS#764 - MT7621: Any traffic shaping results in crashes/stack traces
User who did this - dchard (dchard)

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After 4 days of running, I found this in kernel log:

[168991.950000] ------------[ cut here ]------------
[168991.950000] WARNING: CPU: 2 PID: 0 at net/sched/sch_generic.c:306 dev_watchdog+0x258/0x2fc()
[168991.970000] NETDEV WATCHDOG: eth0 (mtk_soc_eth): transmit queue 0 timed out
[168991.990000] Modules linked in: pppoe ppp_async iptable_nat pppox ppp_generic nf_nat_ipv4 nf_conntrack_ipv6 nf_conntrack_ipv4 ipt_REJECT ipt_MASQUERADE xt_time xt_tcpudp xt_state xt_nat xt_multiport xt_mark xt_mac xt_limit xt_conntrack xt_comment xt_TCPMSS xt_REDIRECT xt_LOG slhc nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_rtcache nf_conntrack iptable_mangle iptable_filter ip_tables crc_ccitt mt76x2e mt7603e ledtrig_usbport mt76 mac80211 cfg80211 compat ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables x_tables leds_gpio xhci_mtk xhci_plat_hcd xhci_pci xhci_hcd gpio_button_hotplug usbcore nls_base usb_common
[168992.110000] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.4.74 #0
[168992.130000] Stack : 00000000 00000000 804c6862 00000033 00000000 00000000 80470000 804e0000
[168992.130000] 	  87c4b9ec 80465c63 803e2840 00000002 00000000 804c367c ffffffff 00000200
[168992.130000] 	  00100000 800650a4 80470000 804e0000 8046a198 8046a19c 803e7160 87c1de04
[168992.130000] 	  00000003 80062df0 ffffffff 00000200 00100000 00000000 00000006 00c1de04
[168992.130000] 	  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[168992.130000] 	  ...
[168992.200000] Call Trace:
[168992.200000] [] show_stack+0x50/0x84
[168992.210000] [] dump_stack+0x84/0xbc
[168992.220000] [] warn_slowpath_common+0xa0/0xd0
[168992.230000] [] warn_slowpath_fmt+0x2c/0x38
[168992.240000] [] dev_watchdog+0x258/0x2fc
[168992.250000] [] call_timer_fn.isra.4+0x24/0x80
[168992.260000] [] run_timer_softirq+0x1fc/0x25c
[168992.270000] [] __do_softirq+0x294/0x2e0
[168992.280000] [] irq_exit+0x78/0x94
[168992.290000] [] plat_irq_dispatch+0xb4/0xdc
[168992.300000] 
[168992.300000] ---[ end trace cc72877aa6acaf37 ]---
[168992.310000] mtk_soc_eth 1e100000.ethernet eth0: transmit timed out
[168992.320000] mtk_soc_eth 1e100000.ethernet eth0: dma_cfg:80000065
[168992.340000] mtk_soc_eth 1e100000.ethernet eth0: tx_ring=0, base=06cf0000, max=512, ctx=449, dtx=449, fdx=448, next=449
[168992.360000] mtk_soc_eth 1e100000.ethernet eth0: rx_ring=0, base=06cf2000, max=512, calc=46, drx=47
[218747.950000] mtk_soc_eth 1e100000.ethernet eth0: transmit timed out
[218747.960000] mtk_soc_eth 1e100000.ethernet eth0: dma_cfg:80000065
[218747.970000] mtk_soc_eth 1e100000.ethernet eth0: tx_ring=0, base=064e6000, max=512, ctx=508, dtx=508, fdx=507, next=508
[218747.990000] mtk_soc_eth 1e100000.ethernet eth0: rx_ring=0, base=06dd6000, max=512, calc=485, drx=486
[218757.950000] mtk_soc_eth 1e100000.ethernet eth0: transmit timed out
[218757.960000] mtk_soc_eth 1e100000.ethernet eth0: dma_cfg:80000065
[218757.970000] mtk_soc_eth 1e100000.ethernet eth0: tx_ring=0, base=06dd6000, max=512, ctx=8, dtx=8, fdx=7, next=8
[218757.990000] mtk_soc_eth 1e100000.ethernet eth0: rx_ring=0, base=064e6000, max=512, calc=279, drx=280


The system log is empty. No restarts or any other way of noticing this except the log entry.

This is with the patched version, maybe completely unrelated.
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=764#comment3027