iMac crashes randomly around once per month

My iMac crashed today the Nth time. I'm not sure why and how this is happening and I'd love some help or next steps. Usually it was happening while I was using it but today it crashed just after I logged in from sleep. Any tips on how to debug this?

panic(cpu 1 caller 0xffffff801aff9a25): userspace watchdog timeout: no successful checkins from com.apple.logd in 120 seconds
service returned not alive with context : unresponsive dispatch queue(s): com.apple.firehose.io-wl 
service: com.apple.logd, total successful checkins since wake (120 seconds ago): 1, last successful checkin: 120 seconds ago
service: com.apple.WindowServer, total successful checkins since wake (120 seconds ago): 2, last successful checkin: 110 seconds ago

Backtrace (CPU 1), Frame : Return Address
0xffffffa13757b670 : 0xffffff8017c8e0dd 
0xffffffa13757b6c0 : 0xffffff8017dd4f33 
0xffffffa13757b700 : 0xffffff8017dc552a 
0xffffffa13757b750 : 0xffffff8017c32a2f 
0xffffffa13757b770 : 0xffffff8017c8d8fd 
0xffffffa13757b890 : 0xffffff8017c8dbf3 
0xffffffa13757b900 : 0xffffff801849d884 
0xffffffa13757b970 : 0xffffff801aff9a25 
0xffffffa13757b980 : 0xffffff801aff9660 
0xffffffa13757b9a0 : 0xffffff801841e13e 
0xffffffa13757b9f0 : 0xffffff801aff8a34 
0xffffffa13757bb20 : 0xffffff801842837b 
0xffffffa13757bc80 : 0xffffff8017d80961 
0xffffffa13757bd90 : 0xffffff8017c9375d 
0xffffffa13757be00 : 0xffffff8017c69cf5 
0xffffffa13757be60 : 0xffffff8017c81312 
0xffffffa13757bef0 : 0xffffff8017da982d 
0xffffffa13757bfa0 : 0xffffff8017c33216 
      Kernel Extensions in backtrace:
         com.apple.driver.watchdog(1.0)[C29AFC04-7113-39AA-80DF-00F4DDAD0F46]@0xffffff801aff7000->0xffffff801aff9fff

Process name corresponding to current thread: watchdogd

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: 0x0000000017a00000
KernelCache base:  0xffffff8017c00000
Kernel slide:      0x0000000017a10000
Kernel text base:  0xffffff8017c10000
__HIB  text base: 0xffffff8017b00000
System model name: iMac18,3 (Mac-BE088AF8C5EB4FA2)
System shutdown begun: NO
Panic diags file available: YES (0x0)
Hibernation exit count: 0

System uptime in nanoseconds: 438271287022502
Last Sleep:           absolute           base_tsc          base_nano
  Uptime  : 0x00018e9afc60d5f1
  Sleep   : 0x00018a6ad4a90c41 0x00000000adcb7fbe 0x00018a350ba3bb24
  Wake    : 0x00018a6ad9578078 0x00000000ae4b5bdc 0x00018a6ad842f370
last started kext at 337525683763293: @filesystems.msdosfs	1.10 (addr 0xffffff7fb34ad000, size 57344)
last stopped kext at 433749007510186: >!UAudio	405.39 (addr 0xffffff7fb27a6000, size 315392)
loaded kexts:
>!UTopCaseDriver	4050.1
@filesystems.smbfs	3.6
>!ATopCaseHIDEventDriver	4050.1
@fileutil	20.036.15
@filesystems.autofs	3.0
>AudioAUUC	1.70
>AGPM	122.1
>!APlatformEnabler	2.7.0d0
>X86PlatformShim	1.0.0
>!AUpstreamUserClient	3.6.8
@kext.AMDFramebuffer	4.0.5
@kext.AMDRadeonX4000	4.0.5
@kext.AMDRadeonServiceManager	4.0.5
>!AHDA	283.15
@kext.AMD9500!C	4.0.5
>eficheck	1
>!A!IKBLGraphics	16.0.4
>!A!IKBLGraphicsFramebuffer	16.0.4
>!AGraphicsDevicePolicy	6.3.3
@AGDCPluginDisplayMetrics	6.3.3
>pmtelemetry	1
|IOUserEthernet	1.0.1
>usb.!UUserHCI	1
|IO!BSerialManager	8.0.5d7
@Dont_Steal_Mac_OS_X	7.0.0
>!AHV	1
>!ADiskImages2	1
>!AGFXHDA	100.1.433
>!A!IPCHPMC	2.0.1
>!AThunderboltIP	4.0.3
>!A!ISlowAdaptiveClocking	4.0.0
|Broadcom!B20703USBTransport	8.0.5d7
>!ASMCLMU	212
>!AMCCSControl	1.14
>Core!SFsck	554
|SCSITaskUserClient	436.121.1
|IO!BUSBDFU	8.0.5d7
>!AFileSystemDriver	3.0.1
@filesystems.tmpfs	1
@filesystems.hfs.kext	556.100.11
@BootCache	40
@!AFSCompression.!AFSCompressionTypeZlib	1.0.0
@!AFSCompression.!AFSCompressionTypeDataless	1.0.0d1
@filesystems.apfs	1677.120.9
>!ASDXC	1.9.0
|!ABCM5701Ethernet	11.0.0
>AirPort.BrcmNIC	1400.1.1
>!AAHCIPort	346.100.2
@private.KextAudit	1.0
>!AACPIButtons	6.1
>!ARTC	2.0
>!ASMBIOS	2.1
>!AACPIEC	6.1
>!AAPIC	1.7
@!ASystemPolicy	2.0.0
@nke.applicationfirewall	311
|IOKitRegistryCompatibility	1
|EndpointSecurity	1
>usb.cdc.ecm	5.0.0
>usb.cdc.ncm	5.0.0
>!UMergeNub	900.4.2
>usb.!UHub	1.2
>!AHIDKeyboard	224
>!AMultitouchDriver	4440.3
>!AInputDeviceSupport	4400.35
>!AHS!BDriver	4050.1
>IO!BHIDDriver	8.0.5d7
@kext.triggers	1.0
@kext.AMDRadeonX4200HWLibs	1.0
@kext.AMDRadeonX4000HWServices	4.0.5
>DspFuncLib	283.15
@kext.OSvKernDSPLib	529
@kext.AMDSupport	4.0.5
|IOAccelerator!F2	442.9
>!AGraphicsControl	6.3.3
>!ASMBusPCI	1.0.14d1
|IOSerial!F	11
|IOAVB!F	940.4
@plugin.IOgPTPPlugin	985.2
|IOEthernetAVB!C	1.1.0
>X86PlatformPlugin	1.0.0
>!AHDA!C	283.15
|IOHDA!F	283.15
>IOPlatformPlugin!F	6.0.0d8
>!AThunderboltDPOutAdapter	8.1.4
|IOAudio!F	300.6.1
@vecLib.kext	1.2.0
@!AGPUWrangler	6.3.3
@!AGraphicsDeviceControl	6.3.3
|IOSlowAdaptiveClocking!F	1.0.0
|Broadcom!BHost!CUSBTransport	8.0.5d7
|IO!BHost!CUSBTransport	8.0.5d7
|IO!BHost!CTransport	8.0.5d7
|IONDRVSupport	585.1
|IOGraphics!F	585.1
>!ASMBus!C	1.0.18d1
>Core!S	554
>usb.IOUSBHostHIDDevice	1.2
>usb.cdc	5.0.0
>usb.networking	5.0.0
>usb.!UHostCompositeDevice	1.2
>!AThunderboltDPInAdapter	8.1.4
>!AThunderboltDPAdapter!F	8.1.4
>!AThunderboltPCIDownAdapter	4.1.1
>!AHPM	3.4.4
>!A!ILpssI2C!C	3.0.60
>!A!ILpssDmac	3.0.60
>!ABSDKextStarter	3
|IOSurface	290.8.1
@filesystems.hfs.encodings.kext	1
>!AXsanScheme	3
|IOAHCIBlock!S	332
>!AThunderboltNHI	7.2.8
|IOThunderbolt!F	9.3.2
|IO80211!F	1200.12.2b1
|IOSkywalk!F	1
>mDNSOffloadUserClient	1.0.1b8
>corecapture	1.0.4
|IONVMe!F	2.1.0
>!A!ILpssI2C	3.0.60
>usb.!UHostPacketFilter	1.0
|IOUSB!F	900.4.2
|IOAHCI!F	294.100.1
>!A!ILpssGspi	3.0.60
>usb.!UXHCIPCI	1.2
>usb.!UXHCI	1.2
>!AEFINVRAM	2.1
>!AEFIRuntime	2.1
|IOSMBus!F	1.1
|IOHID!F	2.0.0
$!AImage4	3.0.0
|IOTimeSync!F	985.2
|IONetworking!F	3.4
>DiskImages	493.0.0
|IO!B!F	8.0.5d7
|IOReport!F	47
|IO!BPacketLogger	8.0.5d7
$quarantine	4
$sandbox	300.0
@kext.!AMatch	1.0.0d1
|CoreAnalytics!F	1
>!ASSE	1.0
>!AKeyStore	2
>!UTDM	511.120.2
|IOUSBMass!SDriver	184.121.1
|IOSCSIBlockCommandsDevice	436.121.1
|IO!S!F	2.1
|IOSCSIArchitectureModel!F	436.121.1
>!AMobileFileIntegrity	1.0.5
@kext.CoreTrust	1
>!AFDEKeyStore	28.30
>!AEffaceable!S	1.0
>!ACredentialManager	1.0
>KernelRelayHost	1
|IOUSBHost!F	1.2
>!UHostMergeProperties	1.2
>usb.!UCommon	1.0
>!ABusPower!C	1.0
>!ASEPManager	1.0.1
>IOSlaveProcessor	1
>!AACPIPlatform	6.1
>!ASMC	3.1.9
|IOPCI!F	2.9
|IOACPI!F	1.4
>watchdog	1
@kec.pthread	1
@kec.corecrypto	11.1
@kec.Libm	1


If you have a M1 Mac, then unplug any USB extenders you may have connected. There is a known problem between M1 Macs and USB extenders, of which Apple doesn't have any answers for yet.

If you do not have a M1 Mac, then the error looks like you may have a corrupt file somewhere causing the computer to do a reboot. In that case, you may have to redo the computer.

Also, check the power connector on the back of the computer. I've had some issues with that in the past. Even shut it down, unplug it and then plug it back in and see what happens.

Hope this helps, Dan Uff

iMac crashes randomly around once per month
 
 
Q