On Tue, Jul 18, 2023 at 08:09:11PM +0100, cho...@jtan.com wrote:

This is completely unrelated to the question we asked. Please
don't hijack the thread.

> Not really. But.
>
> I have an APU2 which runs two VMs that do practically nothing,
> although the box itself is used actively. The VMs consistently, and
> without warning, hang in a way which matches the description "nothing
> new can be execed" although I recall being able to log in on the
> console. I noticed shortly after I installed the VMs in around May
> but I haven't got very far diagnosing it because it's a low priority.
> However there is a common denominator: AMD
>
> cpu0 at mainbus0: apid 0 (boot processor)
> cpu0: AMD G-T40E Processor, 1000.02 MHz, 14-02-00
> cpu0: 
> FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,MMX,FXSR,SSE,SSE2,HTT,SSE3,MWAIT,SSSE3,CX16,POPCNT,NXE,MMXX,FFXSR,PAGE1GB,RDTSCP,LONG,LAHF,CMPLEG,SVM,EAPICSP,AMCR8,ABM,SSE4A,MASSE,3DNOWP,IBS,SKINIT,ITSC
> cpu0: 32KB 64b/line 8-way D-cache, 32KB 64b/line 2-way I-cache
> cpu0: 512KB 64b/line 16-way L2 cache
> cpu0: smt 0, core 0, package 0
>
> Times two.
>
> As you say the existing processes seem to work fine right up until
> sshd is nearly (but not quite?) ready to fork:
>
> .
> .
> .
> debug1: SSH2_MSG_EXT_INFO received
> debug1: kex_input_ext_info: 
> server-sig-algs=<ssh-ed25519,sk-ssh-ed25...@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp...@openssh.com,webauthn-sk-ecdsa-sha2-nistp...@openssh.com,ssh-dss,ssh-rsa,rsa-sha2-256,rsa-sha2-512>
> debug1: kex_input_ext_info: publickey-hostbo...@openssh.com=<0>
> debug1: SSH2_MSG_SERVICE_ACCEPT received
>
> Ordinarily it would next attempt authentication. Does sshd fork and
> drop privileges to do that?
>
> I don't know if that could help or even if it's related, but it can
> be reproduced with confidence. I can poke the box or its VMs any
> way that could shake some data loose.
>
> Matthew
>

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