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From: Fiona Ebner <f.ebner@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: Re: [pve-devel] [PATCH qemu-server] qmeventd: go back to extracting vmid from commandline instead of cgroup file
Date: Mon, 7 Apr 2025 10:32:42 +0200	[thread overview]
Message-ID: <e8978d37-a72e-4d58-87f3-b58457b42d64@proxmox.com> (raw)
In-Reply-To: <20240614092134.18729-1-f.ebner@proxmox.com>

Am 14.06.24 um 11:21 schrieb Fiona Ebner:
> In spirit, this is a revert of 502870a0 ("qmeventd: extract vmid from
> cgroup file instead of cmdline"), but instead of relying on the custom
> 'id' commandline option that's added by a Proxmox VE patch to QEMU,
> rely on the standard 'pidfile' option to extract the VM ID.
> 
> As reported in the community forum [0], at least during stop mode
> backup, it seems to be possible to end up with the VM process having
>> 0::/system.slice/pvescheduler.service
> as its single cgroup entry. It's not clear what exactly happens and
> there was no success to reproduce the issue. Might be a rare bug in
> systemd or in pve-common's enter_systemd_scope() code.
> 
> This was not the first time relying on the cgroup entry caused issues,
> see d0b58753 ("qmeventd: improve getting VMID from PID in presence of
> legacy cgroup entries").
> 
> To avoid such edge cases and issues in the future, go back to
> extracting the VM ID from the process's commandline.
> 
> It's enough to care about the first occurrence of the 'pidfile'
> option, because that's the one added by Proxmox VE, so the 'continue's
> in the loop turn into 'break's. Even though a later option would
> override the first for QEMU itself to use, that's not supported
> anyways and the important part is the VM ID which is present in the
> first.
> 
> [0]: https://forum.proxmox.com/threads/147409/
> 
> Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>

Ping. After it was quiet for ~10 months, there were 2 new reports about
this yesterday:

https://forum.proxmox.com/threads/147409/post-761580


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  reply	other threads:[~2025-04-07  8:33 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-14  9:21 Fiona Ebner
2025-04-07  8:32 ` Fiona Ebner [this message]
2025-04-07 22:53 ` [pve-devel] applied: " Thomas Lamprecht

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