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

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Am 10.02.25 um 12:45 schrieb Michał Pecio:

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On Dell XPS 13 9360/0596KF, BIOS 2.21.0 06/02/2022, with Linux
6.9-rc2+

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Just for the record, I am still seeing this with 6.14.0-rc1

Is this a regression? If so, which versions were not affected?

Unfortunately, I do not know. Right now, my logs go back until September
2024.

     Sep 22 13:08:04 abreu kernel: Linux version 6.11.0-07273-g1e7530883cd2 (build@bohemianrhapsody.molgen.mpg.de) (gcc (Debian 14.2.0-5) 14.2.0, GNU ld (GNU Binutils for Debian) 2.43.1) #12 SMP PREEMPT_DYNAMIC Sun Sep 22 09:57:36 CEST 2024

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How hard to reproduce? Wasn't it during resume from hibernation?

It’s not easy to reproduce, and I believe it’s not related with resuming
from hibernation (which I do not use) or ACPI S3 suspend. I think, I can
force it more, when having the USB-C adapter with only the network cable
plugged into it, and then running `sudo powertop --auto-tune`. But sometimes
it seems unrelated.

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IRQ isuses may be a red herring, this code here is a busy wait under
spinlock. There are a few of those, they cause various problems.

                  if (xhci_handshake(&xhci->op_regs->status,
                                STS_RESTORE, 0, 100 * 1000)) {
                          xhci_warn(xhci, "WARN: xHC restore state timeout\n");
			spin_unlock_irq(&xhci->lock);
                          return -ETIMEDOUT;
                  }

This thing timing out may be close to the root cause of everything.

Interesting. Hopefully the USB folks have an idea.

Handler #08 is NET_RX. So something raised the NET_RX on some non-appropriate
place, perhaps...

Can I ask you one more trace dump?

I need:

echo 1 > /sys/kernel/tracing/events/irq/softirq_raise/enable
echo 1 > /sys/kernel/tracing/options/stacktrace

Unfortunately this will also involve a small patch:

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index fa058510af9c..accd2eb8c927 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c

@@ -1159,6 +1159,9 @@ static bool report_idle_softirq(void)
  	if (local_bh_blocked())
  		return false;
  
+	trace_printk("STOP\n");
+	trace_dump_stack(0);
+	tracing_off();
  	pr_warn("NOHZ tick-stop error: local softirq work is pending, handler #%02x!!!\n",
  		pending);
  	ratelimit++;