[MAJOR ISSUE] b20257, b20262 DNS Server service keeps crashing 0x0374

[Karl_Wester-Ebbinghaus]

Dear Server Insider team,

I am facing the following issue starting with build b20257

DNS Server service keeps crashing and stopped on all ADDS DCs consisting of only hardware and Hyper-V ADDS Servers.

Effectively the domain becomes unuseable. It seems that the crash occours every time a DNS update is incoming

affected builds: Windows Server vNext SAC + LTSC starting with b20257, b20262

unaffected builds: Server vNext SAC + LTSC  b20251 or earlier

Scenario:

3 DCs, 1 Site, Server vNext SAC (2 VMs), LTSC (Hyper-V Server, SET Switch)

Reproducible: yes
Scope: Affects all ADDS Domain Controllers (hardware or physical)

exemplary log:
DNS Service keeps crashing (seems like it does so on every incoming DNS update request).

Servername 1000 Error Application ErrorApplication12.11.2020 21:19:39
Faulting application name: dns.exe, version: 10.0.20257.1000, time stamp: 0x749de11c
Faulting module name: ntdll.dll, version: 10.0.20257.1000, time stamp: 0x12a774b2
Exception code: 0xc0000374
Fault offset: 0x0000000000106489
Faulting process id: 0x36b8
Faulting application start time: 0x01d6b930e2ddeb12
Faulting application path: C:\WINDOWS\system32\dns.exe
Faulting module path: C:\WINDOWS\SYSTEM32\ntdll.dll
Report Id: 67ab2451-27d1-4fb2-a830-270509c59348

When did the issue appear:

after upgrade to 20257.

[#2]

@Mary Hoffman  More than happy to do that. Writing a book with DNS is helped greatly if the DNS server is running! So anything to help! :)

In this case, as reported, DNS starts, but never stays up as reported. So what specific dump types will be helpful? And should I set any specific dump flags? Aiso, should I enable these before upgrade to the latest build or after installation. I hope after, but I have a VM checkpoint and can easily redo it.

Second, which settings should I set for gflags? Will this do it?

I am in the process of upgrading now. :)

gflags /p /enable C:\WINDOWS\system32\dns.exe

[#3]

@Karl_Wester-Ebbinghaus Thanks for that.

I have downloaded the latest ISO and am upgrading one DC now (after moving OPs Master Roles to second DC). Let's see if that cures this issue. I would prefer NOT to have to uninstall DNS and ADDS if I can avoid it, but will do what I can to ensure a working Server.

I'll report shortly on what I find. 

[#4]

SO....

I have updated to the latest Version and the issue persists.

I am unable to find gflags.exe to set the flags. Clues as to where to find this utility?

[#5]

@Thomas Lee  @Mary Hoffman  @Karl_Wester-Ebbinghaus 

So as reported, I downloaded the new version after moving fsmo roles off of dC1 and upgraded. However, the issue persists.

As Mary requested, I set the local dumps (FWIW, the LocalDumps key did not exist, but created it and registry values are requested). :)

After the restart, and setting the local dumps I was successfully able to repo the crash and attach the dump file (zipped).

[#6]

Hi for data protection purposes I would hesitate to upload memory dumps publicly and rather attach your issue and files to feedback hub and link it here
here is my item. Feel free to add here.
https://aka.ms/AAawzdb

[#7]

@Karl_Wester-Ebbinghaus 

I have found the item and uploaded the dump, but so far, Feedback Hub is a black hole with no responses to significant issues like this one! This forum seems much more responsive to major issues with the Insiders builds.

As for data protection, the dump is from a VM with no personal information, so not really worried. I have asked the moderator to remove the post to be on the safe side and have uploaded the dump there.

In the meantime, I have a significant issue with DNS.

[#8]

The suggestion to remove then reinstall DNS has worked. Updating to the latest server dod NOT automatically fix the problem. But on one DC, I removed the dns feature and tools. Rebittef, just to be on the safe side, treinstalled DNS. Since all my zones as AD integrated, they all came back intact and after an hour DNS is stable and working as expected. After 2 hours I repeated the remove and reinstall on DC2 and it, too, is now working.

Thanks for the suggestion!

The solution is DNS, what was the problem?? :)

[#9]

@doctordns i cannot tell the upgrade alone should have worked. in rare cases features and roles may get into inconsistent states as with yours. usually I see this in Server Manager or other RSAT tools, rarely for others. maybe some files were blocked and did not upgrade, or rather registry settings, correctly. I cannot tell. Setup should have had noticed that. 

[#10]

@Karl_Wester-Ebbinghaus 

Thanks for your reply. I can't tell what the cause was, but re-installing DNS did the job!

:)