[FS#1170] mt7621: kernel errors - rcu_sched detected stalls on CPUs/tasks - again

[LEDE Bugs]

The following task has a new comment added:

FS#1170 - mt7621: kernel errors - rcu_sched detected stalls on CPUs/tasks - again
User who did this - Kristian Evensen (kristrev)

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Here is a more detailed trace. Trace was triggered by a network restart during heavy load:

[  686.452081] INFO: rcu_sched self-detected stall on CPU
[  686.457237]  0-...: (5999 ticks this GP) idle=b89/140000000000002/0 softirq=54653/54653 fqs=2895 
[  686.466064]   (t=6000 jiffies g=20069 c=20068 q=101897)
[  686.471268] Task dump for CPU 0:
[  686.474477] swapper/0       R  running task        0     0      0 0x00100004
[  686.481498] Stack : 00000000 8006b3cc 00000000 00000000 00000000 8006b3cc 0000001d 00000006
[  686.489843]         00000006 80471234 00000000 00000000 00000000 00000000 80530000 00000014
[  686.498186]         00000000 804d3f80 804d1490 804d0000 804d1490 00000000 00000000 00000000
[  686.506529]         00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[  686.514871]         00000000 00000000 00000000 00000000 00000000 800a7d00 8fc0dc94 00000000
[  686.523214]         ...
[  686.525650] Call Trace:
[  686.528115] [] show_stack+0x54/0x88
[  686.532458] [] rcu_dump_cpu_stacks+0xdc/0x110
[  686.537686] [] rcu_check_callbacks+0x2cc/0x7c4
[  686.542977] [] update_process_times+0x34/0x70
[  686.548186] [] tick_handle_periodic+0x34/0xd0
[  686.553392] [] gic_compare_interrupt+0x2c/0x40
[  686.558708] [] handle_percpu_devid_irq+0xc4/0x18c
[  686.564255] [] generic_handle_irq+0x24/0x3c
[  686.569291] [] gic_handle_local_int+0x94/0xd4
[  686.574492] [] gic_irq_dispatch+0x10/0x20
[  686.579346] [] generic_handle_irq+0x24/0x3c
[  686.584390] [] do_IRQ+0x1c/0x34
[  686.588385] [] plat_irq_dispatch+0xb4/0xdc
[  686.593326] [] except_vec_vi_end+0xb8/0xc4
[  689.252109] INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 0-... } 6269 jiffies s: 245 root: 0x1/.
[  689.262138] blocking rcu_node structures:
[  689.266130] Task dump for CPU 0:
[  689.269343] swapper/0       R  running task        0     0      0 0x00100004
[  689.276424] Stack : 804c5fe0 804d3f80 00000000 00000000 ffffff80 00000000 00000000 00000340
[  689.284808]         804d148c 00000001 80470cdc 804e0000 00000001 9bff0000 9bfe8000 9bfe8000
[  689.293224]         00000000 803dc644 00000000 00000000 804c4000 804c5ea8 00000000 803dc978
[  689.301789]         804d148c 00000001 80470cdc 804e0000 00000001 80064dac 80530000 804d0000
[  689.310361]         80530000 803da67c 80530000 804d0000 80530000 8051f324 80530000 804f8bac
[  689.318776]         ...
[  689.321222] Call Trace:
[  689.323726] [] __schedule+0x5d4/0x7a4
[  689.328280] [] schedule+0x6c/0x84
[  689.332524] [] schedule_preempt_disabled+0x10/0x1c
[  689.338220] [] cpu_startup_entry+0x15c/0x170
[  689.343434] [] start_kernel+0x444/0x464

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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1170#comment3865