Big Sur panic when connect/disconnect usb-c dock

Unfortunately no answer here, just here to tell that I'm experiencing the same and know how to reproduce it without even using a dock. I need to connect my Dell monitor via USB-C on one of the 2 DisplayPort connections on the monitor. Then I need to turn the display on and off and then it will crash (not all the time, but quite soon).

I've raised a call with Apple Support about this. But apple claims it's a problem with my hardware and not with their software. So now I need to visit a service center to proof that it's their software and not my hardware that is causing the issue.

I am also seeing exactly same thing. Not sure if this is hardware issue/software issue ..or what. Here is crash report, seeing every time laptop goes to sleep. I have thinkvision monitor connected via USB C cable to macbook pro 16" 2019.

====== panic(cpu 10 caller 0xffffff8013c9f846): [kext.kalloc.2048]: element modified after free (off:1672, val:0xfffffffe00000000, sz:2048, ptr:0xffffff9372fb4000, prot:zero)

 1672: 0xfffffffe00000000

Backtrace (CPU 10), Frame : Return Address

0xffffffb0db5aacf0 : 0xffffff801348e0dd

0xffffffb0db5aad40 : 0xffffff80135d4f33

0xffffffb0db5aad80 : 0xffffff80135c552a

0xffffffb0db5aadd0 : 0xffffff8013432a2f

0xffffffb0db5aadf0 : 0xffffff801348d8fd

0xffffffb0db5aaf10 : 0xffffff801348dbf3

0xffffffb0db5aaf80 : 0xffffff8013c9d81a

0xffffffb0db5aaff0 : 0xffffff8013c9f846

0xffffffb0db5ab470 : 0xffffff80134ecad6

0xffffffb0db5ab4e0 : 0xffffff801349d6bc

0xffffffb0db5ab530 : 0xffffff8013bae4f2

0xffffffb0db5ab550 : 0xffffff7fad8f8fce

0xffffffb0db5ab600 : 0xffffff7fad8f965e

0xffffffb0db5ab640 : 0xffffff7fad8b9d86

0xffffffb0db5ab660 : 0xffffff7fae1f3e78

0xffffffb0db5ab900 : 0xffffff7fad8ba924

0xffffffb0db5ab930 : 0xffffff7fae1f5074

0xffffffb0db5ab9c0 : 0xffffff7fae1f30f7

0xffffffb0db5aba10 : 0xffffff7fae1f2ee7

0xffffffb0db5aba60 : 0xffffff7fae1f1f99

0xffffffb0db5abaa0 : 0xffffff8013c1e13e

0xffffffb0db5abaf0 : 0xffffff7fad8ba5e2

0xffffffb0db5abb20 : 0xffffff8013c2837b

0xffffffb0db5abc80 : 0xffffff8013580961

0xffffffb0db5abd90 : 0xffffff801349375d

0xffffffb0db5abe00 : 0xffffff8013469cf5

0xffffffb0db5abe60 : 0xffffff8013481312

0xffffffb0db5abef0 : 0xffffff80135a982d

0xffffffb0db5abfa0 : 0xffffff8013433216

      Kernel Extensions in backtrace:

         com.apple.iokit.IOAcceleratorFamily2(442.9)[BDA1401D-563F-3650-B616-C8073E90475B]@0xffffff7fae1ae000->0xffffff7fae218fff

            dependency: com.apple.driver.AppleMobileFileIntegrity(1.0.5)[366C7BD4-9502-3D1C-ABBE-DE9749913D0C]@0xffffff8014ac0000->0xffffff8014ad5fff

            dependency: com.apple.iokit.IOGraphicsFamily(585.1)[2C81B74F-C771-3643-82EC-12CD4AC5EFDB]@0xffffff7fae32f000->0xffffff7fae35dfff

            dependency: com.apple.iokit.IOPCIFamily(2.9)[99A70889-A31C-3B25-8E88-ADD3F317E4E4]@0xffffff8015f6a000->0xffffff8015f92fff

            dependency: com.apple.iokit.IOReportFamily(47)[367CCAE7-DAB4-3424-B191-44044619D5CB]@0xffffff8015fa1000->0xffffff8015fa3fff

            dependency: com.apple.iokit.IOSurface(290.8.1)[8FA218E4-361C-3C8B-94F0-48434AA535A0]@0xffffff8016094000->0xffffff80160b0fff

         com.apple.driver.AppleIntelKBLGraphics(16.0.4)[F7BCF586-AF08-3277-9C66-04F439E684B4]@0xffffff7fad8a3000->0xffffff7fad95afff

            dependency: com.apple.iokit.IOAcceleratorFamily2(442.9)[BDA1401D-563F-3650-B616-C8073E90475B]@0xffffff7fae1ae000->0xffffff7fae218fff

            dependency: com.apple.iokit.IOGraphicsFamily(585.1)[2C81B74F-C771-3643-82EC-12CD4AC5EFDB]@0xffffff7fae32f000->0xffffff7fae35dfff

            dependency: com.apple.iokit.IOPCIFamily(2.9)[99A70889-A31C-3B25-8E88-ADD3F317E4E4]@0xffffff8015f6a000->0xffffff8015f92fff

            dependency: com.apple.iokit.IOSurface(290.8.1)[8FA218E4-361C-3C8B-94F0-48434AA535A0]@0xffffff8016094000->0xffffff80160b0fff

Process name corresponding to current thread: WindowServer

Boot args: chunklist-security-epoch=0 -chunklist-no-rev2-dev chunklist-security-epoch=0 -chunklist-no-rev2-dev

Mac OS version:

20F71

I had this problem too I removed my ethernet cable from the belkin hub and now its working.

Question to all who have this issue: does your macbook pro have the extra AMD video card in it? Since I went to an apple support center today, assuming I would be able to crash one of their systems as well. Unfortunately I was not able to. But they didn’t have a model with the AMD Radeon Pro in it.

I’m going to an Apple Store next Monday to see if I’ll be able to crash one of their systems, with an AMD onboard. I assume it will be a success, seeing so many here and on reddit having the same issue. But if you have this issue also on macbooks without the AMD in it, then I’m less confident that I’ve isolated the causing factors.

Are you connecting your monitor via DisplayPort? Try using HDMI instead - my laptop only crashes with DisplayPort, never with HDMI. Also, try connecting your monitor without the dock (get a USB-C to HDMI cable) to rule out a problem with dock

@DelGurth mine has AMD Radeon Pro 5300M 4 GB yes

Crash fixed in macOS 12 Monterey beta 2

Little bugs: If I use multiport adapter – I see black screen only on external display (NEC 231WMi). On different external display multiport work ok. If I use non–apple dock and the laptop turns on from sleep mode I see black screen on external display (NEC 231WMi) too, but I can reconnect non–apple dock and I see correct external display working. Apple, please fix this bugs with external display too. Also appeared starting from macos 11.3 to 12 beta 2.

Has anyone tested the Big Sur 11.5 Beta 3 release?

Can confirm - have Radeon pro 5600M 8gb. It does it with Displayport and HDMI on my system. I'm guessing they'll not bother till MacOS Monterey - which has been my experience with EGPU and weird issues like this in the past when they're hard at work on a new OS.

Not great - it's been going on for ages. Hardly what you'd expect when you pay the Apple premium for high end hardware

Big Sur 11.5 beta 4... anyone?

In my case it crashes reproducible if I connect the USB-C hub that has two external monitors connected (either both via HDMI or 1 HDMI and 1 DisplayPort doesn't really matter).

Note: The USB-C hub has two HDMI ports and one DisplayPort, so I can try all kinds of combinations. It also has two USB-C ports for connecting (both) to the MacBook.

It doesn't crash though if one monitor is connected via the USB-C hub and I connect the other monitor directly to one of the MacBook's ports with a USB-C-to-DisplayPort cable.

Sadly, I have the same issue, with a Kensington SD5600T dock, with two 4K external monitors.

Usually, I can get the laptop to boot and both monitors to power on and display an image (not always, though). All it takes to get a crash is to disconnect the Thunderbolt cable and connect it again. I have no issues if I connect the monitors directly to the laptop.

{"caused_by":"macos","macos_version":"Mac OS X 11.4 (20F71)","os_version":"Bridge OS 5.4 (18P4663)","macos_system_state":"running","incident_id":"A55327BC-9C3D-4287-A718-9E95DC783DB8","timestamp":"2021-07-01 08:39:39.00 +0000","bug_type":"210"}
{
  ...
  "build" : "Bridge OS 5.4 (18P4663)",
  "crashReporterKey" : "c0dec0dec0dec0dec0dec0dec0dec0dec0de0001",
  "date" : "2021-07-01 08:39:39.76 +0000",
  "incident" : "A55327BC-9C3D-4287-A718-9E95DC783DB8",
  "kernel" : "Darwin Kernel Version 20.5.0: Fri May  7 22:04:14 PDT 2021; root:xnu-7195.121.3~8\/RELEASE_ARM64_T8010",
  "macOSOtherString" : "\n** In Memory Panic Stackshot Succeeded ** Bytes Traced 400304 (Uncompressed 988640) **\n",
  "macOSPanicFlags" : "0xc",
  "macOSPanicString" : "panic(cpu 1 caller 0xffffff801c09f846): [kext.kalloc.2048]: element modified after free (off:1584, val:0x0000210100000000, sz:2048, ptr:0xffffff937950b000, prot:zero)\n 1584: 0x0000210100000000\n 1592: 0x0000000b00000c00\n 1600: 0x000000010000000d\n 1608: 0x0000061f00000000\n 1616: 0x0000028a00000154\n 1624: 0x0000001000000a00\nBacktrace (CPU 1), Frame : 
...
"panicFlags" : "0x902",
  "panicString" : "panic(cpu 1 caller 0xfffffff011488190): macOS panic detected\nDebugger message: panic\nMemory ID: 0x6\nOS release type: User\nOS version: 18P4663\nmacOS version: 20F71\nKernel version: Darwin Kernel Version 20.5.0: Fri May  7 22:04:14 PDT 2021; root:xnu-7195.121.3~8\/REL
EASE_ARM64_T8010\nKernel UUID: 873F4AC5-B66C-3016-8EAC-39D538EEB5A3\niBoot version: iBoot-6723.120.36\nsecure boot?: YES\nx86 EFI Boot State: 0x16\nx86 System State: 0x0\nx86 Power State: 0x0\nx86 Shutdown Cause: 0xf5\nx86 Previous Power Transitions: 0x70707060400\nPCIeUp link state: 0x892
71614\nPaniclog version: 13\nKernel slide:      0x000000000952c000\n
...

I get the same issue on Dell WD19TB docking station on Macbook pro 16 inch running Big Sur 11.4

No workaround so far

panic(cpu 2 caller 0xffffff8016a9f846): [kext.kalloc.2048]: element modified after free (off:1672, val:0xfffffffe00000000, sz:2048, ptr:0xffffff937493b800, prot:zero)
 1672: 0xfffffffe00000000
Backtrace (CPU 2), Frame : Return Address
0xffffffb0e1c5acf0 : 0xffffff801628e0dd 
0xffffffb0e1c5ad40 : 0xffffff80163d4f33 
0xffffffb0e1c5ad80 : 0xffffff80163c552a 
0xffffffb0e1c5add0 : 0xffffff8016232a2f 
0xffffffb0e1c5adf0 : 0xffffff801628d8fd 
0xffffffb0e1c5af10 : 0xffffff801628dbf3 
0xffffffb0e1c5af80 : 0xffffff8016a9d81a 
0xffffffb0e1c5aff0 : 0xffffff8016a9f846 
0xffffffb0e1c5b470 : 0xffffff80162ecad6 
0xffffffb0e1c5b4e0 : 0xffffff801629d6bc 
0xffffffb0e1c5b530 : 0xffffff80169ae4f2 
0xffffffb0e1c5b550 : 0xffffff7fb06f8fce 
0xffffffb0e1c5b600 : 0xffffff7fb06f965e 
0xffffffb0e1c5b640 : 0xffffff7fb06b9d86 
0xffffffb0e1c5b660 : 0xffffff7fb0ff3e78 
0xffffffb0e1c5b900 : 0xffffff7fb06ba924 
0xffffffb0e1c5b930 : 0xffffff7fb0ff5074 
0xffffffb0e1c5b9c0 : 0xffffff7fb0ff30f7 
0xffffffb0e1c5ba10 : 0xffffff7fb0ff2ee7 
0xffffffb0e1c5ba60 : 0xffffff7fb0ff1f99 
0xffffffb0e1c5baa0 : 0xffffff8016a1e13e 
0xffffffb0e1c5baf0 : 0xffffff7fb06ba5e2 
0xffffffb0e1c5bb20 : 0xffffff8016a2837b 
0xffffffb0e1c5bc80 : 0xffffff8016380961 
0xffffffb0e1c5bd90 : 0xffffff801629375d 
0xffffffb0e1c5be00 : 0xffffff8016269cf5 
0xffffffb0e1c5be60 : 0xffffff8016281312 
0xffffffb0e1c5bef0 : 0xffffff80163a982d 
0xffffffb0e1c5bfa0 : 0xffffff8016233216 
      Kernel Extensions in backtrace:
         com.apple.iokit.IOAcceleratorFamily2(442.9)[BDA1401D-563F-3650-B616-C8073E90475B]@0xffffff7fb0fae000->0xffffff7fb1018fff
            dependency: com.apple.driver.AppleMobileFileIntegrity(1.0.5)[366C7BD4-9502-3D1C-ABBE-DE9749913D0C]@0xffffff80178c0000->0xffffff80178d5fff
            dependency: com.apple.iokit.IOGraphicsFamily(585.1)[2C81B74F-C771-3643-82EC-12CD4AC5EFDB]@0xffffff7fb112f000->0xffffff7fb115dfff
            dependency: com.apple.iokit.IOPCIFamily(2.9)[99A70889-A31C-3B25-8E88-ADD3F317E4E4]@0xffffff8018d6a000->0xffffff8018d92fff
            dependency: com.apple.iokit.IOReportFamily(47)[367CCAE7-DAB4-3424-B191-44044619D5CB]@0xffffff8018da1000->0xffffff8018da3fff
            dependency: com.apple.iokit.IOSurface(290.8.1)[8FA218E4-361C-3C8B-94F0-48434AA535A0]@0xffffff8018e94000->0xffffff8018eb0fff
         com.apple.driver.AppleIntelKBLGraphics(16.0.4)[F7BCF586-AF08-3277-9C66-04F439E684B4]@0xffffff7fb06a3000->0xffffff7fb075afff
            dependency: com.apple.iokit.IOAcceleratorFamily2(442.9)[BDA1401D-563F-3650-B616-C8073E90475B]@0xffffff7fb0fae000->0xffffff7fb1018fff
            dependency: com.apple.iokit.IOGraphicsFamily(585.1)[2C81B74F-C771-3643-82EC-12CD4AC5EFDB]@0xffffff7fb112f000->0xffffff7fb115dfff
            dependency: com.apple.iokit.IOPCIFamily(2.9)[99A70889-A31C-3B25-8E88-ADD3F317E4E4]@0xffffff8018d6a000->0xffffff8018d92fff
            dependency: com.apple.iokit.IOSurface(290.8.1)[8FA218E4-361C-3C8B-94F0-48434AA535A0]@0xffffff8018e94000->0xffffff8018eb0fff

Process name corresponding to current thread: TouchBarServer
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: 0x0000000016000000
KernelCache base:  0xffffff8016200000
Kernel slide:      0x0000000016010000
Kernel text base:  0xffffff8016210000
__HIB  text base: 0xffffff8016100000
System model name: MacBookPro16,1 (Mac-E1008331FDC96864)
System shutdown begun: NO
Hibernation exit count: 20

System uptime in nanoseconds: 73757520514384
Last Sleep:           absolute           base_tsc          base_nano
  Uptime  : 0x0000431502cf50a0
  Sleep   : 0x000040654b0930dd 0x0000570283f01b4a 0x00004058bc1cc29a
  Wake    : 0x0000406587fda601 0x00005f776a0abd50 0x00004065674dd451
last started kext at 70335722390424: >!AWWANSupport1	4.0.0 (addr 0xffffff7fb11c2000, size 20480)
last stopped kext at 71105444164574: >AudioAUUC	1.70 (addr 0xffffff7fb0e20000, size 12288)

Same issue here, this is currently messing up my workday where I sometimes need to connect/disconnect monitors multiple times a day.

Been having the same crash as everyone. I noticed a pattern, The crash seems to happen at Idle times, and a few times I noticed the mouse froze when coming back to the mac moving the mouse around seems to unfreeze the mac. I ordered a "VAYDEER Tiny Mouse Jiggler USB" which causes your cursor to constantly move when you have it on (Assuming any juggler that has the cursors moving constantly will work). Every time I leave the Mac I turn it the "Mouse Jiggler" and for the last week I have not had a Kernel Panic, normally had them a few times a day. Not sure what this proves but I think something on the Mac tries to go to sleep when it is Idle it crashes. If anyone else has a mouse jiggle can you try this and see if it make a difference??