[REGRESSION] ? system is stuck in clocksource, >60s delay at boot time without tsc=unstable

Fab Stz
2024-11-27T07:39:01Z

[-- Attachment #1: Type: text/plain, Size: 4502 bytes --]

Hi,

While upgrading from Debian bullseye (kernel 5.10) to bookworm (6.1) I
noticed that the newer kernel is at the beginning of the boot stuck for
more than 60 seconds.

This is apparently related to the clocksource module. If I boot with
tsc=unstable there is no more delay.

In the kernel logs, I have:

clocksource: Long readout interval, skipping watchdog check: cs_nsec:
512010551 wd_nsec: 39243763320
clocksource: timekeeping watchdog on CPU0: Marking clocksource 'tsc' as
unstable because the skew is too large:
clocksource: 'hpet' wd_nsec: 537773520 wd_now:
3f0f7632 wd_last: 3e425140 mask: ffffffff
clocksource: 'tsc' cs_nsec: 511996079 cs_now:
18b0866e6a cs_last: 185f8d68ba mask: ffffffffffffffff
clocksource: 'tsc' is current clocksource.
tsc: Marking TSC unstable due to clocksource watchdog
TSC found unstable after boot, most likely due to broken BIOS. Use
'tsc=unstable'.
sched_clock: Marking unstable (3765559657, 1276001)<-(3775071370, -8235646)
clocksource: Checking clocksource tsc synchronization from CPU 1 to CPUs 0.
clocksource: Switched to clocksource hpet

I already had such a warning with 5.10, but there was no >60sec freeze
with it like with 6.1

The delay is still present in kernel 6.11.

I attach the output of dmesg. On screen, the last line that is displayed
before being frozen for >60sec is

[ 2.898668] hub 2-0:1.0: 5 ports detected

Because of that, I initially thought that there is a problem with USB,
but actually not since tsc=unstable "fixes" the delay. The kernel
mentions clocksource only later in the logs, but the timestamps don't
reflect the delay. My last measure is a freeze of about 70seconds.

I also noticed that if during that period I do a short press on the
power button of the system, it stops the freeze and the boot process
continues immediately.

Regards

==== System information ====

It's an Apple iMac 9.1

# cat /proc/version
Linux version 6.1.0-28-amd64 (debian-kernel@lists.debian.org) (gcc-12
(Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #1 SMP
PREEMPT_DYNAMIC Debian 6.1.119-1 (2024-11-22)

# hostnamectl | grep "Operating System"
Operating System: Debian GNU/Linux 12 (bookworm)

# uname -mi
x86_64 unknown

# lspci -nn
00:00.0 Host bridge [0600]: NVIDIA Corporation MCP79 Host Bridge
[10de:0a82] (rev b1)
00:00.1 RAM memory [0500]: NVIDIA Corporation MCP79 Memory Controller
[10de:0a88] (rev b1)
00:03.0 ISA bridge [0601]: NVIDIA Corporation MCP79 LPC Bridge
[10de:0aae] (rev b2)
00:03.1 RAM memory [0500]: NVIDIA Corporation MCP79 Memory Controller
[10de:0aa4] (rev b1)
00:03.2 SMBus [0c05]: NVIDIA Corporation MCP79 SMBus [10de:0aa2] (rev b1)
00:03.3 RAM memory [0500]: NVIDIA Corporation MCP79 Memory Controller
[10de:0a89] (rev b1)
00:03.4 RAM memory [0500]: NVIDIA Corporation MCP79 Memory Controller
[10de:0a98] (rev b1)
00:03.5 Co-processor [0b40]: NVIDIA Corporation MCP79 Co-processor
[10de:0aa3] (rev b1)
00:04.0 USB controller [0c03]: NVIDIA Corporation MCP79 OHCI USB 1.1
Controller [10de:0aa5] (rev b1)
00:04.1 USB controller [0c03]: NVIDIA Corporation MCP79 EHCI USB 2.0
Controller [10de:0aa6] (rev b1)
00:06.0 USB controller [0c03]: NVIDIA Corporation MCP79 OHCI USB 1.1
Controller [10de:0aa7] (rev b1)
00:06.1 USB controller [0c03]: NVIDIA Corporation MCP79 EHCI USB 2.0
Controller [10de:0aa9] (rev b1)
00:08.0 Audio device [0403]: NVIDIA Corporation MCP79 High Definition
Audio [10de:0ac0] (rev b1)
00:09.0 PCI bridge [0604]: NVIDIA Corporation MCP79 PCI Bridge
[10de:0aab] (rev b1)
00:0a.0 Ethernet controller [0200]: NVIDIA Corporation MCP79 Ethernet
[10de:0ab0] (rev b1)
00:0b.0 SATA controller [0106]: NVIDIA Corporation MCP79 AHCI Controller
[10de:0ab9] (rev b1)
00:0c.0 PCI bridge [0604]: NVIDIA Corporation MCP79 PCI Express Bridge
[10de:0ac4] (rev b1)
00:10.0 PCI bridge [0604]: NVIDIA Corporation MCP79 PCI Express Bridge
[10de:0aa0] (rev b1)
00:15.0 PCI bridge [0604]: NVIDIA Corporation MCP79 PCI Express Bridge
[10de:0ac6] (rev b1)
00:16.0 PCI bridge [0604]: NVIDIA Corporation MCP79 PCI Express Bridge
[10de:0ac7] (rev b1)
03:00.0 VGA compatible controller [0300]: NVIDIA Corporation C79
[GeForce 9400] [10de:0867] (rev b1)
04:00.0 Network controller [0280]: Broadcom Inc. and subsidiaries
BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b] (rev 01)
05:00.0 FireWire (IEEE 1394) [0c00]: LSI Corporation FW643 [TrueFire]
PCIe 1394b Controller [11c1:5901] (rev 07)

[-- Attachment #2: dmesg.noparam.txt.gz --]
[-- Type: application/gzip, Size: 23540 bytes --]