Big Sur panic when connect/disconnect usb-c dock

Exact same system as you, Belkin Thunderbolt 3 Pro dock here. Same symptoms on 11.4.

I've had the logic board in this machine replaced twice now, bugs logged with Apple support etc. It's very easy to reproduce as others say.

This, in addition to the ethernet driver not working as of Big Sur is another reason I think Apple's QC is going down the pan. Totally unacceptable to have this critical bug in a release OS.

HI ,

Same issue here when I am connecting to my MCP 16 BigSur 11.4 my Docking station my laptop panic and reboot him self it didn't happened the las version before only now .

any update on it. ?

panic(cpu 8 caller 0xffffff8003c9f846): [kext.kalloc.2048]: element modified after free (off:1672, val:0xffffffff00000000, sz:2048, ptr:0xffffff9362ecd000, prot:zero) 1672: 0xffffffff00000000 Backtrace (CPU 8), Frame : Return Address 0xffffffb0cacbab60 : 0xffffff800348e0dd 0xffffffb0cacbabb0 : 0xffffff80035d4f33 0xffffffb0cacbabf0 : 0xffffff80035c552a 0xffffffb0cacbac40 : 0xffffff8003432a2f 0xffffffb0cacbac60 : 0xffffff800348d8fd 0xffffffb0cacbad80 : 0xffffff800348dbf3 0xffffffb0cacbadf0 : 0xffffff8003c9d81a 0xffffffb0cacbae60 : 0xffffff8003c9f846 0xffffffb0cacbb2e0 : 0xffffff80034ecad6 0xffffffb0cacbb350 : 0xffffff800349d6bc 0xffffffb0cacbb3a0 : 0xffffff8003bae4f2 0xffffffb0cacbb3c0 : 0xffffff800655a41c 0xffffffb0cacbb3e0 : 0xffffff80065683fc 0xffffffb0cacbb440 : 0xffffff800655ab6e 0xffffffb0cacbb4e0 : 0xffffff800655df0e 0xffffffb0cacbb790 : 0xffffff800655b073 0xffffffb0cacbb8f0 : 0xffffff8006550377 0xffffffb0cacbb950 : 0xffffff8006554e88 0xffffffb0cacbbb10 : 0xffffff8003c8536e 0xffffffb0cacbbb60 : 0xffffff80037488af 0xffffffb0cacbbc70 : 0xffffff800373d95d 0xffffffb0cacbbf40 : 0xffffff8003b3fc9e 0xffffffb0cacbbfa0 : 0xffffff80034331f6 Kernel Extensions in backtrace: com.apple.security.sandbox(300.0)[C7CC6439-6854-33FB-9E97-F468B75AD280]@0xffffff8006549000->0xffffff800658efff dependency: com.apple.driver.AppleMobileFileIntegrity(1.0.5)[366C7BD4-9502-3D1C-ABBE-DE9749913D0C]@0xffffff8004ac0000->0xffffff8004ad5fff dependency: com.apple.iokit.IOStorageFamily(2.1)[A0D72FE9-649B-316A-8B5C-934E295FF0B5]@0xffffff800606d000->0xffffff800607efff dependency: com.apple.kext.AppleMatch(1.0.0d1)[759DEBDE-C844-3703-A01C-4DF5EEA8F4ED]@0xffffff8004abc000->0xffffff8004abefff

Process name corresponding to current thread: NotificationCenter Boot args: chunklist-security-epoch=0 -chunklist-no-rev2-dev

Mac OS version: 20F71

Kernel version: Darwin Kernel Version 20.5.0: Sat May 8 05:10:33 PDT 2021; root:xnu-7195.121.3~9/RELEASE_X86_64 Kernel UUID: 52A1E876-863E-38E3-AC80-09BBAB13B752 KernelCache slide: 0x0000000003200000 KernelCache base: 0xffffff8003400000 Kernel slide: 0x0000000003210000 Kernel text base: 0xffffff8003410000 __HIB text base: 0xffffff8003300000 System model name: MacBookPro16,1 (Mac-E1008331FDC96864) System shutdown begun: NO Hibernation exit count: 0

All my problems started with the update to 11.4, before that I was using 11.2 and had no problems. The error is happening when I connect a second usb-c dock to HDMI to be able to use two external HDMI monitors, as soon I connect the second dongle, is go straight to the kernel error.

Frustrating indeed.

I contacted Apple Support and was escalated to a senior Mac advisor. I showed him this thread, and his immediate response was that because it is not reproduced with the Apple Multiport Adapter, it is a third-party issue.

I insisted, and explained thoroughly, that this is an issue that was introduced by an Apple update, is caused by Apple's GPU drivers, and it's unacceptable that the solution to a botched update is that I buy a 3-port $69.99 adapter.

I was told that they don't control third parties, "things change", and they don't control their drivers.

Frankly, Apple has a responsibility to make sure they don't introduce updates that make previously functional accessories crash our computers. I was told that unless I can present a convincing argument, the case will be closed because it is only affecting third-party adapters.

I explained that if the case is closed I will dedicate however long is needed to reverse-engineer the drivers and diagnose the issue, and come back with a solid case. They then promptly collected diagnostics and had me reproduce the crash three times (which happened one after another), and escalated the case to engineers out of generosity.

While this has been escalated to engineers, I don't have high hopes that this will be fixed for us. If the sentiment that was shown to me is shared by the rest of Apple, the solution is going to be that we need to buy their multiport adapter and accept it. Completely unprofessional, and certainly not a way to keep me on as a customer.

Alas Apple Support is not able to help me any further. The only fix they can provide is connecting via HDMI and not via usb-c -> DisplayPort (so far I've not been able to crash my system once it's connected via HDMI).

The Senior Advisers are not able to get through to Engineering, the feedback stays: it's a problem with the 3rd party hardware, not our system. If only this happened to a famous streamer. The HDMI solution sucks, since it means I'll only have 1 usb-c port free. But it's better than crashes.

Updating to Monterey BETA 2 fixed the issue for me as well :)

I'm on BigSur 11.4 with the same issue as describe: plug-in USB-C Dell monitor results mostly in system crashes, 1m - 2h later during web conferences / work. Same crash reports as posted here many times.

% sw_vers
ProductName:	macOS
ProductVersion:	11.4
BuildVersion:	20F71

Updating to Monterey BETA 2 fixed the issue for me as well :)

Can somebody explain how to get this beta?

Big Sur 11.5 Beta 5 is out... anyone?

Just realised one of my Dell monitors has an option to use DisplayPort 1.1 (instead of the default 1.2) and in this mode it doesn't seem to crash my laptop. I'll leave this running for another while to see if it gets around the problem.

Of course this option might not be available in more recent monitors and also DP 1.1 is very limiting in terms of resolution/refresh rate (it can't run 4K at 60fps) but for anyone with lower res monitors suffering daily crashes this might be a better compromise until Apple get their act together.

Finally! macOS Monterey 12.0 beta fixes the issue for me.

MacBook Pro 16 2019, connected to a Kapok USB-C PD Hub (https://www.amazon.ca/Adapter-Docking-Station-Monitors-Windows/dp/B08QVPY28N/ref=sr_1_6) connected to a 65W power adapter and a 4K HDMI 1.4 monitor.

With previous OS versions (tried 11.4 and 11.5 beta 5) I could easily reproduce the crash. With 12.0 beta I ran about 5 minutes of plug-unplug at 10-15 seconds of interval and my system is still up and running, stable.

Good luck to the rest of you!

Has anyone tried the 11.5 release candidate... I'm not holding my breath...

I have the same issue with my iMac 2021.

After I shut down my mac, it restarted and I got a Problem Report for MacOS prompt saying it was a Kernel version: Darwin Kernel Version 20.4.0. I searched the issue right away in Google and found out about this thread. True enough, I'm using my Baseus USB-C Dock for the first time. Hope they'll fix it soon.

Same here. Calldigit dock with 2 mons. Sometimes, it's also enough to only connect the monitor (HDMI) to the dock.

It's quite frustrating, to reboot the laptop on every dock connecting..

Same issue with MacBook Pro (16-inch, 2019) and HP Z27k G3 by connect & disconnect the monitor.

System: MacBook Pro (16-inch, 2019)

OS Version: Big Sur 11.4 (20F71)

Graphics: AMD Radeon Pro 5500M 4 GB, Intel UHD Graphics 630 1536 MB

I had encountered the same problem. Unplug and Plug USB-C cable to MacBook and Kernal panic 'element modified after free'. I'm following this thread from quite sometime now just to find any fix/workaround.

Home setup: dual monitors - DELL P2421DC directly connecting via USB-C cable (cable is from Dell, out of box with new monitors).

Office setup: dual monitors - DELL U3821DW directly connecting via USB3.1 Type C cable (80C 30V - is printed on wire) -> https://www.bizlinktech.com/products/detail/1240/USB+3.1+Gen+2+Type-C+Active+Cable

And surprisingly when I connected my MBP to external monitors in office last week, no crashes. I tested my home setup with Bizlink USB3.1 Type C cable and didn't encountered any crashes so far. I'm not sure how these cables differ. I couldn't find anything written on Dell USB-C cable to figure out.