[FS#804] mt7621: kernel errors - rcu_sched detected stalls on CPUs/tasks

[LEDE Bugs]

The following task has a new comment added:

FS#804 - mt7621: kernel errors - rcu_sched detected stalls on CPUs/tasks
User who did this - Pierre Parent (pparent76)

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After I continued testing I finally got a message:

[  328.780000] INFO: rcu_sched detected stalls on CPUs/tasks:
[  328.780000] 	1-...: (1 GPs behind) idle=15a/0/0 softirq=17882/17884 fqs=0 
[  328.780000] 	3-...: (0 ticks this GP) idle=39c/0/0 softirq=19473/19473 fqs=0 
[  328.780000] 	(detected by 0, t=6002 jiffies, g=6144, c=6143, q=27828)
[  328.780000] Task dump for CPU 1:
[  328.780000] swapper/1       R  running task        0     0      1 0x00100000
[  328.780000] Stack : 8fc73fe0 0000fc00 00000000 00001400 00000000 00000009 00000000 0000024e
[  328.780000]         804bf48c 00000002 8045f424 804d0000 00000001 00000001 bfbf8000 00000001
[  328.780000]         00000000 8000c1cc 00000000 00000000 8fc72000 8fc73f00 00000000 80062ea4
[  328.780000]         1100fc03 00000003 00000001 804d0000 804bf48c 80062e9c 00000000 00000001
[  328.780000]         00000001 00000001 00000000 00000001 00000001 00000001 00000001 9fc0046c
[  328.780000]         ...
[  328.780000] Call Trace:
[  328.780000] [] __schedule+0x5d4/0x7a4
[  328.780000] [] r4k_wait_irqoff+0x0/0x20
[  328.780000] Task dump for CPU 3:
[  328.780000] swapper/3       R  running task        0     0      1 0x00100000
[  328.780000] Stack : 00000068 00000001 00000001 001fb940 00000000 77ddc2c0 00000000 00000000
[  328.780000]         804bf48c 00000008 8045f424 804d0000 00000001 00000001 bfbf8000 00000003
[  328.780000]         00000000 8000c1cc 00000000 00000000 8fc76000 8fc77f00 00000000 80062ea4
[  328.780000]         1100fc03 00000003 00000001 804bf48c 804bf48c 80062e9c 00000001 00000001
[  328.780000]         00000001 00000001 00000001 00000001 00000001 00000001 00000001 9fc0046c
[  328.780000]         ...
[  328.780000] Call Trace:
[  328.780000] [] __schedule+0x5d4/0x7a4
[  328.780000] [] r4k_wait_irqoff+0x0/0x20
[  328.780000] rcu_sched kthread starved for 6002 jiffies! g6144 c6143 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x1
[  328.780000] rcu_sched       S    0     7      2 0x00100000
[  328.780000] Stack : 814b5bc0 8fc52340 8fc6be50 814b4320 8fc6be50 00000000 00000000 8007b4a8
[  328.780000]         814b4320 fffff3cd 814b4320 8fc6be50 804c0000 00000001 804c0000 804c0000
[  328.780000]         804c75b0 803ca9f4 fffff3cd 804c0000 8fc6be50 814b4320 fffff3cd 803cd358
[  328.780000]         804bf5f4 00000000 804c0000 804c0000 814b6240 00000001 00000000 814b43b0
[  328.780000]         fffff3cd 8007b9a4 8fc52340 03800003 804c7480 00000001 804c0000 00000000
[  328.780000]         ...
[  328.780000] Call Trace:
[  328.780000] [] __schedule+0x5d4/0x7a4
[  328.780000] [] schedule+0x6c/0x84
[  328.780000] [] schedule_timeout+0x160/0x19c
[  328.780000] [] rcu_gp_kthread+0x7f4/0x7fc
[  328.780000] [] kthread+0xd8/0xec
[  328.780000] [] ret_from_kernel_thread+0x14/0x1c
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=804#comment3093