Re: NOHZ tick-stop error: local softirq work is pending, handler #08!!! on Dell XPS 13 9360

Paul Menzel
2024-08-21T08:20:55Z

Dear Anna-Maria,

Thank you very much for the support. I was finally able to collect the
data you asked for.

Am 09.04.24 um 09:57 schrieb Anna-Maria Behnsen:
> Paul Menzel writes:

[…]

>> Am 08.04.24 um 12:10 schrieb Anna-Maria Behnsen:
>>
>>> Paul Menzel writes:
>>
>>>> On Dell XPS 13 9360/0596KF, BIOS 2.21.0 06/02/2022, with Linux 6.9-rc2+
>>>> built from commit b1e6ec0a0fd0 (Merge tag 'docs-6.9-fixes' of
>>>> git://git.lwn.net/linux) the external USB-C adapter Dell DA300 stopped
>>>> working (only the Ethernet port was used). Linux logged:
>>>
>>> thanks for the report. Can you please provide a trace beside the dmesg
>>> output? The following trace events should be enabled (via kernel command
>>> line):
>>>
>>> trace_event=timer:*,timer_migration:*,sched:sched_switch,sched:sched_wakeup,sched:sched_process_hang,irq:softirq_entry,irq:softirq_raise,irq:softirq_exit
>> Unfortunately I haven’t been able to reproduce it until now. Should it
>> happen again, I am going to try your suggestion.
>
> Thanks for letting me know.

I wanted to configure that in the running system, but wasn’t able to set
all of these at once with `set_event`:

echo
'timer:*,timer_migration:*,sched:sched_switch,sched:sched_wakeup,sched:sched_process_hang,irq:softirq_entry,irq:softirq_raise,irq:softirq_exit'
| sudo tee /sys/kernel/tracing/set_event

For some reason setting them individually also did *not* work:

for e in timer:* timer_migration:* sched:sched_switch
sched:sched_wakeup sched:sched_process_hang irq:softirq_entry
irq:softirq_raise irq:softirq_exit'; do echo "$e" | sudo tee -a
/sys/kernel/tracing/set_event; done

I then used

echo 1 | sudo tee /sys/kernel/tracing/events/timer/enable
echo 1 | sudo tee /sys/kernel/tracing/events/timer_migration/enable
echo 1 | sudo tee /sys/kernel/tracing/events/sched/sched_switch/enable
echo 1 | sudo tee /sys/kernel/tracing/events/sched/sched_wakeup/enable
echo 1 | sudo tee
/sys/kernel/tracing/events/sched/sched_process_hang/enable
echo 1 | sudo tee /sys/kernel/tracing/events/irq/softirq_entry/enable
echo 1 | sudo tee /sys/kernel/tracing/events/irq/softirq_raise/enable
echo 1 | sudo tee /sys/kernel/tracing/events/irq/softirq_exit/enable

and also had to increase the buffer to bridge the gap between the event
and me noticing it:

echo 96000 | sudo tee /sys/kernel/tracing/buffer_size_kb

Then, with Linux v6.11-rc4-11-g521b1e7f4cf0b, I was able to get the
trace for the event below:

[ 7542.706299] NOHZ tick-stop error: local softirq work is pending,
handler #08!!!

$ sudo cat /sys/kernel/tracing/trace
[…]
MediaPD~der #28-14000 [000] d..1. 7542.703768: hrtimer_cancel:
hrtimer=000000008d2c9f3f
MediaPD~der #28-14000 [000] ..... 7542.703810: hrtimer_init:
hrtimer=00000000c6f259e7 clockid=CLOCK_MONOTONIC mode=ABS
MediaPD~der #28-14000 [000] d..1. 7542.703812: hrtimer_start:
hrtimer=00000000c6f259e7 function=hrtimer_wakeup expires=7602581538204
softexpires=7602581488204 mode=ABS
MediaPD~der #28-14000 [000] d..2. 7542.703821: sched_switch:
prev_comm=MediaPD~der #28 prev_pid=14000 prev_prio=120 prev_state=S ==>
next_comm=swapper/0 next_pid=0 next_prio=120
<idle>-0 [000] dN.2. 7542.703931: sched_wakeup:
comm=ImageBridgeChld pid=6041 prio=120 target_cpu=000
<idle>-0 [000] d..2. 7542.703937: sched_switch:
prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==>
next_comm=ImageBridgeChld next_pid=6041 next_prio=120
ImageBridgeChld-6041 [000] d..2. 7542.704041: sched_switch:
prev_comm=ImageBridgeChld prev_pid=6041 prev_prio=120 prev_state=S ==>
next_comm=swapper/0 next_pid=0 next_prio=120
<idle>-0 [000] dN.2. 7542.704174: sched_wakeup:
comm=Renderer pid=4113 prio=120 target_cpu=000
<idle>-0 [000] d..2. 7542.704179: sched_switch:
prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==>
next_comm=Renderer next_pid=4113 next_prio=120
Renderer-4113 [000] d..2. 7542.704245: sched_switch:
prev_comm=Renderer prev_pid=4113 prev_prio=120 prev_state=S ==>
next_comm=swapper/0 next_pid=0 next_prio=120
<idle>-0 [000] dNh2. 7542.704260: sched_wakeup:
comm=IPC I/O Child pid=6029 prio=120 target_cpu=000
<idle>-0 [000] d..2. 7542.704267: sched_switch:
prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==>
next_comm=IPC I/O Child next_pid=6029 next_prio=120
IPC I/O Child-6029 [000] d..2. 7542.704340: sched_switch:
prev_comm=IPC I/O Child prev_pid=6029 prev_prio=120 prev_state=S ==>
next_comm=swapper/0 next_pid=0 next_prio=120
<idle>-0 [000] dN.2. 7542.704786: sched_wakeup:
comm=Compositor pid=4123 prio=120 target_cpu=000
<idle>-0 [000] d..2. 7542.704791: sched_switch:
prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==>
next_comm=Compositor next_pid=4123 next_prio=120
Compositor-4123 [000] d..2. 7542.704944: sched_switch:
prev_comm=Compositor prev_pid=4123 prev_prio=120 prev_state=S ==>
next_comm=swapper/0 next_pid=0 next_prio=120
<idle>-0 [000] dN.2. 7542.705943: sched_wakeup:
comm=Compositor pid=4123 prio=120 target_cpu=000
<idle>-0 [000] d..2. 7542.705950: sched_switch:
prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==>
next_comm=Compositor next_pid=4123 next_prio=120
Compositor-4123 [000] d..2. 7542.706105: sched_switch:
prev_comm=Compositor prev_pid=4123 prev_prio=120 prev_state=S ==>
next_comm=swapper/0 next_pid=0 next_prio=120
<idle>-0 [000] d.h2. 7542.706328: hrtimer_cancel:
hrtimer=000000009bbda66a
<idle>-0 [000] d.h1. 7542.706329:
hrtimer_expire_entry: hrtimer=000000009bbda66a
function=tick_nohz_handler now=7542584007490
<idle>-0 [000] d.h1. 7542.706333: softirq_raise: vec=9
[action=RCU]
<idle>-0 [000] d.h1. 7542.706338: softirq_raise: vec=7
[action=SCHED]
<idle>-0 [000] d.h1. 7542.706339: hrtimer_expire_exit:
hrtimer=000000009bbda66a
<idle>-0 [000] d.h2. 7542.706340: hrtimer_start:
hrtimer=000000009bbda66a function=tick_nohz_handler
expires=7542588000000 softexpires=7542588000000 mode=ABS
<idle>-0 [000] ..s1. 7542.706345: softirq_entry: vec=7
[action=SCHED]
<idle>-0 [000] ..s1. 7542.706359: softirq_exit: vec=7
[action=SCHED]
<idle>-0 [000] ..s1. 7542.706360: softirq_entry: vec=9
[action=RCU]
<idle>-0 [000] ..s1. 7542.706362: softirq_exit: vec=9
[action=RCU]
<idle>-0 [000] dNh4. 7542.707672: sched_wakeup:
comm=irq/51-DLL075B: pid=194 prio=49 target_cpu=000
<idle>-0 [000] d..2. 7542.707685: sched_switch:
prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==>
next_comm=irq/51-DLL075B: next_pid=194 next_prio=49
irq/51-DLL075B:-194 [000] ..... 7542.707708: timer_init:
timer=00000000630ae178
irq/51-DLL075B:-194 [000] d..1. 7542.707710: timer_start:
timer=00000000630ae178 function=process_timeout expires=4296778179
[timeout=250] bucket_expiry=4296778184 cpu=0 idx=121 flags=
irq/51-DLL075B:-194 [000] d..2. 7542.707718: sched_switch:
prev_comm=irq/51-DLL075B: prev_pid=194 prev_prio=49 prev_state=D ==>
next_comm=swapper/0 next_pid=0 next_prio=120
<idle>-0 [000] dN.2. 7542.709072: sched_wakeup:
comm=AudioIP~ent RPC pid=6671 prio=120 target_cpu=000
[…]

The trace file is 320 MB big. If you need the full trace and log, please
tell me, and I’ll upload it somewhere.

Kind regards,

Paul