mac OS Catalina 10.15 – Watchdog Timeout Kernel Panic

In the last few days, when I shutdown my iMac, it takes a long long time, freezes, then restarts with this report – which is always basically the same. I have already reseted PRAM and SMC. If someone could help me out understand what's going on, it would be great.

panic(cpu 1 caller 0xffffff7f837afaae): watchdog timeout: no checkins from watchdogd in 302 seconds (5030 totalcheckins since monitoring last enabled), shutdown in progress
Backtrace (CPU 1), Frame : Return Address
0xffffff82bd8dbc40 : 0xffffff800211868d 
0xffffff82bd8dbc90 : 0xffffff8002252ab5 
0xffffff82bd8dbcd0 : 0xffffff800224463e 
0xffffff82bd8dbd20 : 0xffffff80020bea40 
0xffffff82bd8dbd40 : 0xffffff8002117d57 
0xffffff82bd8dbe40 : 0xffffff8002118147 
0xffffff82bd8dbe90 : 0xffffff80028bf328 
0xffffff82bd8dbf00 : 0xffffff7f837afaae 
0xffffff82bd8dbf10 : 0xffffff7f837af486 
0xffffff82bd8dbf50 : 0xffffff7f837c4d9c 
0xffffff82bd8dbfa0 : 0xffffff80020be13e 
      Kernel Extensions in backtrace:
         com.apple.driver.watchdog(1.0)[B6A95892-6C75-3CF5-A6CC-6D83F30FA1D5]@0xffffff7f837ae000->0xffffff7f837b6fff
         com.apple.driver.AppleSMC(3.1.9)[D2F0B610-83F8-3B84-B0BD-D9D0CC95A697]@0xffffff7f837b7000->0xffffff7f837d5fff
            dependency: com.apple.iokit.IOACPIFamily(1.4)[2956198D-24F2-3790-A9B2-1EAB9434B906]@0xffffff7f837a5000
            dependency: com.apple.driver.watchdog(1)[B6A95892-6C75-3CF5-A6CC-6D83F30FA1D5]@0xffffff7f837ae000
            dependency: com.apple.iokit.IOPCIFamily(2.9)[2F37AE58-E6B9-3B18-9092-3B80D34C334B]@0xffffff7f82b31000

BSD process name corresponding to current thread: kernel_task

Mac OS version:
19H15

Kernel version:
Darwin Kernel Version 19.6.0: Thu Oct 29 22:56:45 PDT 2020; root:xnu-6153.141.2.2~1/RELEASE_X86_64
Kernel UUID: 9B5A7191-5B84-3990-8710-D9BD9273A8E5
Kernel slide:     0x0000000001e00000
Kernel text base: 0xffffff8002000000
__HIB  text base: 0xffffff8001f00000
System model name: iMac14,2 (Mac-27ADBB7B4CEE8E61)
System shutdown begun: YES
Panic diags file available: YES (0x0)

System uptime in nanoseconds: 50625992870163
last loaded kext at 44848782795591: >usb.cdc.acm    5.0.0 (addr 0xffffff7f85fa3000, size 32768)
last unloaded kext at 44911847112129: >!UMergeNub   900.4.2 (addr 0xffffff7f85f77000, size 12288)
loaded kexts:
>!ATopCaseHIDEventDriver    3430.1
>AudioAUUC  1.70
@fileutil   20.036.15
>!APlatformEnabler  2.7.0d0
>AGPM   111.4.4
>X86PlatformShim    1.0.0
>!AMikeyHIDDriver   131
@filesystems.autofs 3.0
>!AMikeyDriver  283.15
>!AHDA  283.15
>!A!IHD5000Graphics 14.0.7
@AGDCPluginDisplayMetrics   5.2.6
>!A!IFramebufferAzul    14.0.7
>!AHV   1
|IOUserEthernet 1.0.1
|IO!BSerialManager  7.0.6f7
>pmtelemetry    1
@Dont_Steal_Mac_OS_X    7.0.0
>!ABacklight    180.3
>!AUpstreamUserClient   3.6.8
>!AMCCSControl  1.14
@GeForce    14.0.0
>eficheck   1
>!ASMCLMU   212
>!AThunderboltIP    3.1.4
>!ALPC  3.1
>!A!ISlowAdaptiveClocking   4.0.0
>!AVirtIO   1.0
@filesystems.hfs.kext   522.100.5
@!AFSCompression.!AFSCompressionTypeDataless    1.0.0d1
@BootCache  40
@!AFSCompression.!AFSCompressionTypeZlib    1.0.0
@filesystems.apfs   1412.141.1
@private.KextAudit  1.0
>!ASDXC 1.7.7
>AirPort.BrcmNIC    1400.1.1
|!ABCM5701Ethernet  10.3.5
>!AAHCIPort 341.140.1
>!ARTC  2.0
>!AACPIButtons  6.1
>!AHPET 1.8
>!ASMBIOS   2.1
>!AACPIEC   6.1
>!AAPIC 1.7
$!AImage4   1
@nke.applicationfirewall    303
$TMSafetyNet    8
@!ASystemPolicy 2.0.0
|EndpointSecurity   1
>usb.cdc.ncm    5.0.0
>usb.cdc    5.0.0
>!A!BHIDKeyboard    209
>!AHIDKeyboard  209
>!AMultitouchDriver 3440.1
>!AInputDeviceSupport   3440.8
>!AHS!BDriver   3430.1
>IO!BHIDDriver  7.0.6f7
@kext.triggers  1.0
>DspFuncLib 283.15
@kext.OSvKernDSPLib 529
|IOAVB!F    850.1
>!ABacklightExpert  1.1.0
>!ASMBus!C  1.0.18d1
|IOAccelerator!F2   438.7.3
>!ASMBusPCI 1.0.14d1
@nvidia.driver.NVDAGK100Hal 14.0.0
@nvidia.driver.NVDAResman   14.0.0
>!AThunderboltEDMSink   4.2.3
>X86PlatformPlugin  1.0.0
>IOPlatformPlugin!F 6.0.0d8
@!AGPUWrangler  5.2.6
@!AGraphicsDeviceControl    5.2.6
|IOSlowAdaptiveClocking!F   1.0.0
>!AHDA!C    283.15
|IOHDA!F    283.15
|IONDRVSupport  576.1
|IOGraphics!F   576.1
@plugin.IOgPTPPlugin    840.3
|Broadcom!BHost!CUSBTransport   7.0.6f7
|IO!BHost!CUSBTransport 7.0.6f7
|IO!BHost!CTransport    7.0.6f7
|IO!B!F 7.0.6f7
|IO!BPacketLogger   7.0.6f7
>usb.!UHub  1.2
>usb.networking 5.0.0
>usb.!UHostCompositeDevice  1.2
|IOAudio!F  300.2
@vecLib.kext    1.2.0
|IOSerial!F 11
@filesystems.hfs.encodings.kext 1
|IOSurface  269.11
>!AThunderboltDPOutAdapter  6.2.6
>!AThunderboltDPInAdapter   6.2.6
>!AThunderboltDPAdapter!F   6.2.6
>!AThunderboltPCIDownAdapter    2.5.4
|IOAHCIBlock!S  316.100.5
>!AThunderboltNHI   5.8.6
|IOThunderbolt!F    7.6.1
|IO80211!F  1200.12.2b1
>corecapture    1.0.4
|IOSkywalk!F    1
|IOUSB!F    900.4.2
|IOEthernetAVB!C    1.1.0
>mDNSOffloadUserClient  1.0.1b8
>usb.!UXHCIPCI  1.2
>usb.!UXHCI 1.2
|IOAHCI!F   290.0.1
>!AEFINVRAM 2.1
>!AEFIRuntime   2.1
|IOSMBus!F  1.1
|IOHID!F    2.0.0
$quarantine 4
$sandbox    300.0
@kext.!AMatch   1.0.0d1
>DiskImages 493.0.0
>!AFDEKeyStore  28.30
>!AEffaceable!S 1.0
>!ASSE  1.0
>!AKeyStore 2
>!UTDM  489.120.1
|IOSCSIBlockCommandsDevice  422.120.3
>!ACredentialManager    1.0
>KernelRelayHost    1
>!ASEPManager   1.0.1
>IOSlaveProcessor   1
|IOUSBMass!SDriver  157.140.1
|IOSCSIArchitectureModel!F  422.120.3
|IO!S!F 2.1
|IOUSBHost!F    1.2
>!UHostMergeProperties  1.2
>usb.!UCommon   1.0
>!ABusPower!C   1.0
|CoreAnalytics!F    1
>!AMobileFileIntegrity  1.0.5
@kext.CoreTrust 1
|IOTimeSync!F   840.3
|IONetworking!F 3.4
|IOReport!F 47
>!AACPIPlatform 6.1
>!ASMC  3.1.9
>watchdog   1
|IOPCI!F    2.9
|IOACPI!F   1.4
@kec.pthread    1
@kec.Libm   1
@kec.corecrypto 1.0

Solution 1:

My personal experience of a similar issue on Big Sur (Intel) lead me to the external monitor.

I now have to disconnect the external monitor before shutdown. I would suggest that you try the same and also with any other devices you have connected.

I also had a similar issue with Catalina as well which was related to the external monitor's audio driver and my bluetooth headset. which caused issues with shutdowns and sleep mode often leading to Kernel panic reports when I booted up the following day.

It is most likely a software bug, however, can begotten around physisically.