[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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I am testing with latest trunk (patches already included), but after 6 days of error free operation, today I got this:

[509232.226713] ------------[ cut here ]------------
[509232.236114] WARNING: CPU: 2 PID: 0 at net/sched/sch_generic.c:316 dev_watchdog+0x254/0x2f4
[509232.252761] NETDEV WATCHDOG: eth0 (mtk_soc_eth): transmit queue 0 timed out
[509232.266800] Modules linked in: nf_nat_tftp nf_nat_snmp_basic nf_nat_sip nf_nat_pptp nf_nat_proto_gre nf_nat_irc nf_nat_h323 nf_nat_amanda nf_conntrack_tftp nf_conntrack_snmp nf_conntrack_sip nf_conntrack_pptp nf_conntrack_proto_gre nf_conntrack_irc nf_conntrack_h323 nf_conntrack_broadcast nf_conntrack_amanda ts_kmp ts_fsm ts_bm pppoe ppp_async pppox ppp_generic nf_conntrack_ipv6 iptable_nat 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 xt_CT slhc nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_conntrack_ipv4 nf_nat_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 ledtrig_usbport mt76 mac80211
[509232.407717]  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
[509232.446222] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.9.37 #0
[509232.458159] Stack : 00000000 00000000 80547b2a 00000033 80402a44 00000000 00000000 80540000
[509232.474972]         87c4c3bc 804e7ea7 8047e9ec 00000002 00000000 80543824 ffffffff 00000200
[509232.491781]         00200000 800699b0 00000001 80540000 804edfc4 804edfc8 8048361c 87c1dddc
[509232.508599]         00000003 800a7888 ffffffff 00000200 00200000 00000000 00000006 00c1dddc
[509232.525409]         00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[509232.542215]         ...
[509232.547243] Call Trace:
[509232.552294] [] show_stack+0x54/0x88
[509232.561142] [] dump_stack+0x84/0xc0
[509232.569975] [] __warn+0xe4/0x118
[509232.578288] [] warn_slowpath_fmt+0x30/0x3c
[509232.588345] [] dev_watchdog+0x254/0x2f4
[509232.597872] [] call_timer_fn.isra.3+0x24/0x84
[509232.608432] [] run_timer_softirq+0x1e0/0x240
[509232.618825] [] __do_softirq+0x294/0x2e0
[509232.628347] [] irq_exit+0x7c/0x98
[509232.636843] [] plat_irq_dispatch+0xb4/0xdc
[509232.646998] ---[ end trace 30d36c65571c506e ]---
[509232.656368] mtk_soc_eth 1e100000.ethernet eth0: transmit timed out
[509232.668868] mtk_soc_eth 1e100000.ethernet eth0: dma_cfg:80000065
[509232.681021] mtk_soc_eth 1e100000.ethernet eth0: tx_ring=0, base=06c30000, max=512, ctx=210, dtx=210, fdx=209, next=210
[509232.702505] mtk_soc_eth 1e100000.ethernet eth0: rx_ring=0, base=073c0000, max=512, calc=442, drx=443

It is intersting, as I tortured the patched version for hours with both 100% CPU load and iperf3 tests in the same time, yet I got nothing. And today, out of the blue I got this error again. No crashes, no reboot, no any other sign of this event except the kernel log entry.


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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#comment3191