Running Ventura 13.0.1 on a Macbook Pro 2019 (Intel)
Occasionally–several times a day, at what seem like random times–MacOS gets into a temporary state in which it seems to get stuck launching new processes. That is, the symptoms are:
- Already running apps & desktop still seem to mostly work; I can interact, move windows around, open menus, etc.
- Entering a command in a shell freezes the shell
- Opening a new tab in a browser freezes the browser
- Trying to open a new app from LaunchBar freezes LaunchBar
- After some amount of time (typically 1-2 minutes), it unfreezes and all the queued up things launch: browser tab loads, shell command runs, etc. And then everything works normally… until the next time.
I.e. it seems to me that when a process tries to launch a child process, the fork() syscall hangs for a while, and in the meantime the parent process is blocked and so unresponsive. If so, it seems like there could be some sort of resource lock/deadlock in the kernel that needs to time out? Of course I could be way off base on all this, maybe something else is going on.
I haven’t noticed any pattern for what triggers this. It only started happening after I updated to Ventura — post hoc ergo procter hoc? I’ve tried the obvious coarse hammers: rebooting, resetting PRAM & SMC. I don’t see anything in the Console logs.
Any ideas for what might be happening? How to debug it? And of course how to fix it? 
Update: It just happened again, I could pull down iStat menus while new processes were stuck. More things I found:
- During the stuck time,
kernel_taskbopped up and down between 20% and 92% CPU; after the stuck time,kernel_taskis back down around 3%.RTProtectionDaemonwas also bouncing up to 100% and back down, but it does that also when not in the stuck time. No other CPU activity of note. - Answering @mmmmmm’s comment: Memory pressure 10%, Memory 55%. No sign of any process swapping hog.