Since installing Catalina yesterday, multiple crashes from userspace watchdog timeout

I also have experienced no more crashes since the 10.15.6 update, at least so far. (MBP 16" 2019 in clamshell mode with one external display.) I hope for everyone else's benefit that Apple fixes this for all soon! Baby steps are better than none at all, I guess.

It's been around a week now and I have not had a single problem with these crashes anymore. I've been using my 16" MBP in clam shell mode, plugging, unplugging, leaving it overnight connected to the display, etc., and it feels rock solid again like I am used to Macs feeling.

All my energy settings are default, with the laptop going to sleep whilst plugged in and connected to an external display, etc.

Very happy now however I WILL NOT be so fast to in updating the OS next time an update is available. I will probably wait a good 3-5 months post Big Sur release too, thanks to this experience.

I'd had a nightmare of crashes with my MacBook Pro 16, 2019 model with Catalina versions up to 10.15.3.

However since around 10.15.4 the crashes are no longer occurring at all.

Not sure exactly how it happened ( at the time I doubted my Akitio 10GB Ethernet dock and two 4k monitors ), but one thing I remember is that after being frustrated with 10.15.4, I tried clean install of everything.

I know how frustrating it can be to be told "try re-installing everything",

but to me Catalina 10.15.6 is perfectly stable, if anyone is still experiencing problems, why not give it one last chance, with a clean install.

While I have had 2 crashes since updating to 10.15.6 last Friday, I must admit that the system DOES seem slightly more stable (again, I was having daily, if not MULTIPLE daily, crashes before the update). Will keep my own log of issues, so that I can accurately remember how many issues I encounter with the latest update. I can live with 1 crash a week (not that I would be happy with that, but it's certainly better than many times per week!), so let's see how it goes over the next few weeks.

I also turned off Spotlight, for what that is worth -- I really don't rely on what it does anyway (file/app indexing), and noticed that it was often spiking my CPU and causing my fan to run. Not saying that helped or hurt anything -- just adding more info... :)

Same here on a 6 week old 13" MBP with i7 and 32 GB memory, factory shipped with 10.15.5, upgraded to 10.15.6, still crashing without warning.

Not related to a dedicated GPU as I've seen some folk speculate as the 13" models don't have one.

From the watchdogd man page:

WATCHDOGD(8) BSD System Manager's Manual WATCHDOGD(8)

NAME

watchdogd -- watchdog daemon

DESCRIPTION

watchdogd ensures that the system is healthy and able to make forward progress throughout the system lifecycle.

If watchdogd or the Watchdog KEXT determine that the system is unhealthy they will attempt to take corrective action and ultimately may panic the system to get it back to a usable state.

This command is not intended to be invoked directly.

Darwin November 9, 2018 Darwin

The FreeBSD (the userland of which Darwin, the underlying platform for macOS, is based upon) man page for watchdogd goes into more detail and states that

The watchdogd utility interfaces with the kernel's	watchdog facility to
     ensure that the system is in a working state.  If watchdogd is unable to
     interface with the	kernel over a specific timeout,	the kernel will	take
     actions to	assist in debugging or restarting the computer.

and that

One possible circumstance which will cause	a watchdog timeout is an in-
     terrupt storm.  If	this occurs, watchdogd will no longer execute and thus
     the kernel's watchdog routines will take action after a configurable
     timeout.

There was a kernel extension (/System/Library/Extensions) in Mojave named AppleOSXWatchdog.kext, but that kernel extension is completely missing in Catalina. Maybe it was replaced by /System/Library/PrivateFrameworks/WatchdogClient.framework ?

We need our contributor who works on kernels every day to comment please!

I wonder what would happen if we copied the AppleOSXWatchdog.kext from Mojave to Catalina...??

Hi

(easyread bit)

Certainly from my experience where the screen freezes I don't believe that the watchdog is the cause of the problem, just the program which catches it.

panic(cpu 6 caller 0xffffff7f912faad5): userspace watchdog timeout: no successful checkins from com.apple.WindowServer in 120 seconds

So the WindowServer that drives the desktop display stop responding, watchdog notices this and after it has been unresponsive for 2 minutes restarts the system.

(easyreaders stop here :)

As for interrupt storm, anything is a possibility. I haven't found a pattern to the hangs yet. Although in my case it's definitely the WindowServer which is hanging first. Everything except the mouse pointer freezes (including toolbar apps like clock).

I would love to be able to find out what WindowServer is waiting for when it hangs. Might give a few clues.

I know many are seeing this when the system is sleeping or otherwise involved in power saving, but others, like myself, are seeing this whilst the system is actively being used.

... there is a glimmer of hope though. 10.15.6 (release) has now been stable for a couple of days. Even if it crashes now that is far better than the previous release / betas which were struggling to survive a couple of hours.

It's possible. kexts can be dynamically loaded by other kexts or the configuration of multiple kexts can be bundled into a catch all kext (such as USB chipset compatibility, for example) which may have happened from 10.14 -> 10.15, though I don't have time to check this out.

As far as using the Mojave kext goes, here be dragons. It might work flawlessly (my Mac Pro 5.1 does this with the Airport kext for Wifi support and it works flawlessly - the Catalina one simply removed the config for that older Broadcom chipset so I could equally have hacked the Catalina kext if I was less lazy), but it might also result in a bricked system that needs single user mode or worse, mounting the volume in target disk mode on another machine, to roll back.

If you decide to test it out please report back with your findings.

Same problem after Catalina 10.15.6 (19G73) update...

Configuration:

MacBook Pro (15-inch, 2017)

2,9 GHz Quad-Core Intel Core i7

16 GB 2133 MHz LPDDR3

Radeon Pro 560 4 GB

Intel HD Graphics 630 1536 MB

Given those odds (and the comments from DOL_Mark that the WatchDog is likely not the primary cause), I probably will not risk this. I'm not afraid of single user mode, but I think the odds are low for success.

Hard to believe that such frequent kernel panics are continuing in Catalina for so long, but I'll add one more data point that might be helpful. I just purchased a new MacBook Air that came with Catalina and then immediately upgraded to 10.15.6. I did not (yet) migrate from my previous MBP or restore a TimeMachine backup. I only just started installing a few apps and configured the system settings. I haven't yet plugged in my external monitors or done much of anything that could be implicated in the kernel panics. Yet they have been happening to me as well -- 4 crashes (due to the same userspace watchdog timeout kernel panic) within the first two days of my purchase. The only thing that might have stressed the system was an attempt to set up TimeMachine to back it up with an external drive plugged into a USB hub. The drive was fairly full with backups from an old MBP. So, I deleted a large number of the old backups and ran "Empty Trash", which chugged away for hours. When I came back later, I noticed that my system had crashed and rebooted. That same scenario repeated several more times before I called Apple Support, who (after probably checking this same community forum thread and similar threads), suggested that I uncheck "Put hard disks to sleep when possible" in the Energy Saver System Preferences. I'm now waiting to see if that does the trick (though if it does, that's still a lousy mitigation option since it will reduce battery life over time if this is never resolved otherwise).

My MBP15 2018 doesn't crash on 10.15.5 or 10.15.6 unless it's connected to one or more external monitors.

When connected to external monitors, it will crash at least once every 2 hours, sometimes more frequently.

This is regardless of the combination of settings in the Energy Saver panel.

My only work-around is to have my MBP15i7 2013 (still a great machine with a superb keyboard) drive the three external monitors, and vnc to the MBP15i9 2018 to run a few demanding apps. Obviously, this would not be a good workaround if I were trying to do video editing, where I would need the MBP15i9 2018 directly connected to external monitors.

Thinking that Sidecar was perhaps a very significant (video feature) addition to Catalina, I went into the Sidecar preference panel and unchecked the checked-by-default "Show Sidebar" and "Show Touch Bar" picks. I have no idea of the extent to which this may or may not "disable" Sidecar. Then I put the MBP15i9 2018 back into a 3 external monitor setup, which I run with the lid open, giving 4 effective monitors. I did this yesterday evening. No crashes yet. But need to get through a full week-day of strenuous use before saying that this made any improvement.

I have passed to Catalina 10.15.6 without any improvement, my iMac 21.5" 4K late 2015 continues to crash very often.

My feeling is the problem is caused by video driver, probably an Intel revenge issue :-)

Anyway, my iMac is unusable. I'm very disappointed. I hope this issue will share with other potential customers!!!