Hi Thomas, Do you have any quick suggestion before report it on CentOS? thanks Cliff
-- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1879425 Title: The thread of "CPU 0 /KVM" keeping 99.9%CPU Status in QEMU: Incomplete Bug description: Hi Expert: The VM is hung here after (2, or 3, or 5 and the longest time is 10 hours) by qemu-kvm. Notes: for VM: OS: RHEL8.1 CPU: 1 MEM:4G For qemu-kvm(host kernel RHEL7): 1) version: /usr/libexec/qemu-kvm -version QEMU emulator version 2.10.0(qemu-kvm-ev-2.10.0-21.el7_5.4.1) 2) once the issue is occurred, the CPU of "CPU0 /KVM" is more than 99% by com "top -p VM_pro_ID" PID UDER PR NI RES S % CPU %MEM TIME+ COMMAND 872067 qemu 20 0 1.6g R 99.9 0.6 37:08.87 CPU 0/KVM 3) use "pstack 493307" and below is function trace Thread 1 (Thread 0x7f2572e73040 (LWP 872067)): #0 0x00007f256cad8fcf in ppoll () from /lib64/libc.so.6 #1 0x000055ff34bdf4a9 in qemu_poll_ns () #2 0x000055ff34be02a8 in main_loop_wait () #3 0x000055ff348bfb1a in main () 4) use strace "strace -tt -ff -p 872067 -o cfx" and below log keep printing 21:24:02.977833 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 0}, NULL, 8) = 0 (Timeout) 21:24:02.977918 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 911447}, NULL, 8) = 0 (Timeout) 21:24:02.978945 ppoll([{fd=4, events=POLLIN}, {fd=6, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=115, events=POLLIN}, {fd=121, events=POLLIN}], 9, {0, 0}, NULL, 8) = 0 (Timeout) Therefore, I think the thread "CPU 0/KVM" is in tight loop. 5) use reset can recover this issue. however, it will reoccurred again. Current work around is increase one CPU for this VM, then issue is gone. thanks Cliff To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1879425/+subscriptions
