Latest ElCap upgrade hanging 10.11.6 - "Stalling for detach"

Same, but different hardware: MacPro (late 2013 trashcan); El Capitan 10.11.6.

1/4/17 9:28:06.000 AM kernel[0]: stalling for detach from AMDTahitiGraphicsAccelerator

Just stalled while I was writing this.

@cgn - could you please check your build number (About this mac -> System report -> Software), which seems to be more relevant here than the form of your trash can 😉 ; and check which updates you applied recently?

15G1212 seems to be the common thread. Is there a way to roll that update back? The problem it introduced are WAY worse than whatever they were trying to fix. It was happening a couple of times a minute for me last night. I rebooted and it's not happened since, though I've used it more casually since then.

I filed a bugreport with Apple.

I was able to get a repeatable hang while using Outlook 365. Safari was also running. After UI became responsive I quit Safari, and the problem disappeared. The console log entries make me think that the WindowServer was somehow corrupted by Safari. I can load the log (from which I've stripped an enormous amount of un-responded-to pings) if there is any interest.

Two machines, MacBook Air and Mac Pro, Both having OS X 10.11.6 (15G1212), have this problem.

Error messages from system.log:

Jan 4 17:24:44 MacPro kernel[0]: stalling for detach from AMDTahitiGraphicsAccelerator

Jan 4 14:05:49 MacBookAir kernel[0]: stalling for detach from IntelAccelerator

Switching from Safari to Chrome can provide some relief from the problem, but other apps such as VLC may sometimes trigger it.

Safari is Version 10.0.2 (11602.3.12.0.1)

I have been having the same issue on my mid-2012 non-Retina MacBook Pro that has both Intel graphics and NVidia GPU, with OS-X 10.11.6. The issue is not CPU load or memory load; I can watch it happen with only a couple of gigabytes of user application and only background tasks engaged in any activity. This last time I happened to be able to start Activity Monitor and noticed the spindump executing which led me to the log files that showed the detach messages for nvAccelerator.

As some others described, I was able to ssh in and the system was responsive.

Earlier today (before I saw the log entries), I got control back by shooting Firefox, which was the largest application at the time. More recently, I got control back by shooting Maple, which uses a Java user interface. In both of those particular cases, Maple was running. I seem to recall that I have also had this difficulty when Maple was not running but when MATLAB was running; MATLAB also uses a Java user interface. It is possible that I am misremembering: it is possible that I did have Maple running at the time as well (but shooting MATLAB was what did the trick then.)

I do not have VMWare running on my system at all. I do have Parallels, but it was not active this afternoon.

So, the commonalities are on the 2012 machine, and with a Java-based program executing at the time of the trouble. Killing one of my user processes gets it un-hung, but it is not necessarily the Java-based process that needs to be killed in my experience.

I got a request from Apple for more info in my bug report today, so will see what response I get. As with others, the failing build is 15G1212.

One other datapoint is that if you look at the kernel source code at opensource.apple.com, the "stalling for detach" message is only in the source code for 10.12.1 (Sierra), not 10.11.6 (El Capitan). However, the 10.11.6 source code is "xnu-3248.60.10" while a system running build 15G1212 seems to be "xnu-3248.60.11.1.2~2".

This seems to confirm that the original 10.11.6 was probably OK, but also implies that whatever changed between xnu-3248.60.10 and xnu-3248.60.11.1.2~2 may have caused the bug. Luckily this is a small version number change, so hopefully this makes it easier to find the problematic change.

It also implies that upgrading to Sierra may not help though 😟

A short time ago, I was beginning to be affected again while using MATLAB, but originally not badly. I seemed to be having graphics problems (graphics not showing up) so I quit MATLAB. At that point I went into the stall. The only user applications I was left running were Firefox and Slack. I ssh'd in, shot firefox, and got back control immediately.

Checking around, I find that firefox is not written in Java at all, so it is not clear that the problem is Java. However, as MATLAB is Java based, it just might be the case that using Java somehow triggers the problem but that then quitting that Java program might not (always) be enough. It could be the case, for example, that what is required is to quit some windowed program and that could hypothetically trigger a state cleanup .

I am not getting stalling for detach from IntelAccelerator where I was not before. And now the only user application I am running is Firefox.

I can also now seem to provoke Firefox to hang by asking to Save Link As of the MCC 6220 User Manual on the page http://www.mccdaq.com/products/6220.htm -- I get a save window that is has a thick black stripe on the left and is otherwise empty and gives the spinning beach ball. My system stability seems to be deteriorating, so I am going to reboot right after posting this.

If this helps anyone, I've found that I can fix the stalling/freezes by quitting Photoshop (2017.0.1). I'm wondering if this is because Photoshop uses the GPU and is really just the manifestation of a bug on the macOS graphics layer. So, for some it might be another app that is using the GPU for accelerated graphics, and causing the issue. I've seen some can fix the problem by quitting Safari. Your mileage may vary. And it's definitely no a permanent solution, as the problem comes back, but a quicker bandaid to apply than having to restart the entire system.

It appears that many applications can cause stall, and freeze up the UI, including Safari, Outlook, Photoshop, etc. I originally thought Safari was the culprit, but have duplicated freeze without any browser running.

Seems that quitting Photoshop is only a solution as long as I don't want to run Photoshop any longer. As soon as I open it up again, the freezing returns. Hmmmm.... looks like I will have to hard reboot.

So it looks like we are all experiencing the same issue. I installed the update on the 18th. Haven't restarted my machine since then. Today I came back to it after not using it since Xmas day and as soon as I started to work there was the problem. I quit safari, used firefox, same issues. I quit outlook and opened only safari, same issue. I have been scouring the security update document line by line to see if I can find the culprit. Also speaking with apple but they just want me to run disk utility.

Hey everyone. Quick update. Spoke to apple tech on the phone for a while today trying to narrow this down. We could find nothing. We did notice that no one here mentioned booting into safe mode to see if the issue could be recreated or went away. For me after a reboot (before safe mode) it went away. Of course this doesn't mean that we're out of the woods but just a quick FYI.