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+kernel: 0.911
+hypervisor: 0.828
+virtual: 0.818
+files: 0.810
+device: 0.790
+graphic: 0.763
+performance: 0.693
+register: 0.688
+permissions: 0.599
+PID: 0.588
+vnc: 0.586
+semantic: 0.552
+socket: 0.546
+ppc: 0.539
+risc-v: 0.512
+arm: 0.467
+user-level: 0.458
+i386: 0.457
+debug: 0.455
+architecture: 0.455
+VMM: 0.437
+boot: 0.412
+mistranslation: 0.408
+x86: 0.386
+TCG: 0.341
+network: 0.293
+KVM: 0.254
+assembly: 0.206
+peripherals: 0.136
+
+qemu-ga fsfreeze crashes the kernel
+Description of problem:
+Hello,
+
+Still required your attention, duplicate from:
+https://bugs.launchpad.net/bugs/1807073
+https://bugs.launchpad.net/bugs/1813045
+
+We use mainly Cloudlinux, Debian and Centos.
+We experienced many crashes on our qemu instances based on Cloudlinux during a snapshot.
+The issue is not related to CloudLinux directly, but to Qemu agent, which does not freeze the file system(s) correctly. What is actually happening:
+
+When VM backup is invoked, Qemu agent freezes the file systems, so no single change will be made during the backup. But Qemu agent does not respect the loop* devices in freezing order (we have checked its sources), which leads to the next situation:
+1) freeze loopback fs
+              ---> send async reqs to loopback thread
+2) freeze main fs
+3) loopback thread wakes up and trying to write data to the main fs, which is still frozen, and this finally leads to the hung task and kernel crash.
+
+Moreover, a lot of Proxmox users are complaining about the issue as well:
+https://forum.proxmox.com/threads/error-vm-100-qmp-command-guest-fsfreeze-thaw-failed-got-timeout.68082/
+https://forum.proxmox.com/threads/problem-with-fsfreeze-freeze-and-qemu-guest-agent.65707/
+Steps to reproduce:
+1. Manually start backup for the VM with qemu-agent enabled.
+2. The backup process stuck at "INFO: issuing guest-agent 'fs-freeze' command"
+3. The VM become unavailable, you can only unlock it and force reset.
+Additional information:
+/var/log/messages logs:  
+Aug  6 21:54:00 cpanel qemu-ga: info: guest-ping called  
+Aug  6 21:54:01 cpanel qemu-ga: info: guest-fsfreeze called  
+Aug  6 21:54:01 cpanel qemu-ga: info: executing fsfreeze hook with arg 'freeze'  
+
+
+after this the VM becomes completely unavailable.