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I can reproduce this. The reproducer can actually be simplified as follows:
$ qemu-img create -f raw /tmp/test.img 64M
$ qemu-system-x86_64 \
-object iothread,id=thread0 \
-object throttle-group,x-iops-total=40,id=tg0 \
-blockdev file,filename=/tmp/test.img,node-name=file \
-blockdev throttle,file=file,throttle-group=tg0,node-name=disk \
-device virtio-scsi-pci,iothread=thread0 \
-device scsi-hd,drive=disk \
-qmp stdio <<EOF
{"execute":"qmp_capabilities"}
{"execute": "blockdev-reopen", "arguments": {"options": [
{"driver": "throttle","node-name": "disk", "file": "fmt",
"throttle-group": "tg0"}]}}
EOF
The problem seems to be that qmp_blockdev_reopen() calls bdrv_subtree_drained_end() without taking the AioContext lock for the BlockDriverState.
Passed testing on
Red Hat Enterprise Linux release 9.0 Beta (Plow)
5.14.0-56.el9.x86_64
qemu-kvm-6.2.0-9.el9.x86_64
seabios-bin-1.15.0-1.el9.noarch
edk2-ovmf-20220126gitbb1bba3d77-2.el9.noarch
virtio-win-prewhql-0.1-215.iso
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (new packages: qemu-kvm), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2022:2307
Description of problem: Qemu crash after execute block-reopen with iothread. qemu: qemu_mutex_unlock_impl: Operation not permitted #0 0x00007f3fc651d7fc __pthread_kill_implementation (libc.so.6 + 0x8f7fc) #1 0x00007f3fc64d0676 raise (libc.so.6 + 0x42676) #2 0x00007f3fc64ba7d3 abort (libc.so.6 + 0x2c7d3) #3 0x0000564ec7fc6da2 qemu_mutex_unlock_impl (qemu-kvm + 0x966da2) #4 0x0000564ec7e3329f bdrv_subtree_drained_end (qemu-kvm + 0x7d329f) #5 0x00007f3fc6808ba0 g_slist_foreach (libglib-2.0.so.0 + 0x6dba0) #6 0x00007f3fc680db6f g_slist_free_full (libglib-2.0.so.0 + 0x72b6f) #7 0x0000564ec7debf7c qmp_blockdev_reopen (qemu-kvm + 0x78bf7c) #8 0x0000564ec7f0ce9f qmp_marshal_blockdev_reopen (qemu-kvm + 0x8ace9f) #9 0x0000564ec7fb72a7 do_qmp_dispatch_bh (qemu-kvm + 0x9572a7) #10 0x0000564ec7fc2cd1 aio_dispatch (qemu-kvm + 0x962cd1) #11 0x0000564ec7fdcf02 aio_ctx_dispatch (qemu-kvm + 0x97cf02) #12 0x00007f3fc67efd4f g_main_context_dispatch (libglib-2.0.so.0 + 0x54d4f) #13 0x0000564ec7fe9bc3 main_loop_wait (qemu-kvm + 0x989bc3) #14 0x0000564ec7c63d57 qemu_main_loop (qemu-kvm + 0x603d57) #15 0x0000564ec79bc6f2 main (qemu-kvm + 0x35c6f2) #16 0x00007f3fc64bb560 __libc_start_call_main (libc.so.6 + 0x2d560) #17 0x00007f3fc64bb60c __libc_start_main@@GLIBC_2.34 (libc.so.6 + 0x2d60c) #18 0x0000564ec79bbdb5 _start (qemu-kvm + 0x35bdb5) Version-Release number of selected component (if applicable): Red Hat Enterprise Linux release 9.0 Beta (Plow) 5.14.0-47.el9.x86_64 qemu-kvm-6.2.0-5.el9.x86_64 seabios-bin-1.15.0-1.el9.noarch edk2-ovmf-20210527gite1999b264f1f-8.el9.noarch virtio-win-prewhql-0.1-215.iso Same issue also found on qemu-kvm-6.1.0-8.el9.x86_64 How reproducible: 100% Steps to Reproduce: 1.Create images qemu-img create -f qcow2 /home/kvm_autotest_root/images/stg1.qcow2 11G qemu-img create -f qcow2 /home/kvm_autotest_root/images/stg2.qcow2 12G 2.boot VM and enable iothread /usr/libexec/qemu-kvm \ -name 'avocado-vt-vm1' \ -sandbox on \ -machine q35 \ -device pcie-root-port,id=pcie-root-port-0,multifunction=on,bus=pcie.0,addr=0x1,chassis=1 \ -device pcie-pci-bridge,id=pcie-pci-bridge-0,addr=0x0,bus=pcie-root-port-0 \ -nodefaults \ -device VGA,bus=pcie.0,addr=0x2 \ -m 8G \ -smp 10,maxcpus=10,cores=5,threads=1,dies=1,sockets=2 \ -cpu 'Cascadelake-Server-noTSX',+kvm_pv_unhalt \ \ -device pcie-root-port,id=pcie-root-port-1,port=0x1,addr=0x1.0x1,bus=pcie.0,chassis=2 \ -device qemu-xhci,id=usb1,bus=pcie-root-port-1,addr=0x0 \ -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1 \ -object iothread,id=iothread0 \ -object iothread,id=iothread1 \ -object throttle-group,x-iops-total=40,id=group1 \ -object throttle-group,x-iops-total=50,id=group2 \ -device pcie-root-port,id=pcie-root-port-2,port=0x2,addr=0x1.0x2,bus=pcie.0,chassis=3 \ -device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pcie-root-port-2,addr=0x0,iothread=iothread0 \ -blockdev node-name=file_image1,driver=file,auto-read-only=on,discard=unmap,aio=threads,filename=/home/kvm_autotest_root/images/rhel900-64-virtio-scsi.qcow2,cache.direct=on,cache.no-flush=off \ -blockdev node-name=drive_image1,driver=qcow2,read-only=off,cache.direct=on,cache.no-flush=off,file=file_image1 \ -device scsi-hd,id=image1,drive=drive_image1,write-cache=on \ -blockdev node-name=file_stg1,driver=file,auto-read-only=on,discard=unmap,aio=threads,filename=/home/kvm_autotest_root/images/stg1.qcow2,cache.direct=on,cache.no-flush=off \ -blockdev node-name=qcow2_stg1,driver=qcow2,file=file_stg1,read-only=off,cache.direct=on,cache.no-flush=off \ -blockdev node-name=drive_stg1,driver=throttle,throttle-group=group1,file=qcow2_stg1 \ -device scsi-hd,id=stg1,drive=drive_stg1,write-cache=on,serial=TARGET_DISK1 \ -blockdev node-name=file_stg2,driver=file,auto-read-only=on,discard=unmap,aio=threads,filename=/home/kvm_autotest_root/images/stg2.qcow2,cache.direct=on,cache.no-flush=off \ -blockdev node-name=qcow2_stg2,driver=qcow2,file=file_stg2,read-only=off,cache.direct=on,cache.no-flush=off \ -blockdev node-name=drive_stg2,driver=throttle,throttle-group=group1,file=qcow2_stg2 \ -device scsi-hd,id=stg2,drive=drive_stg2,write-cache=on,serial=TARGET_DISK2 \ -device pcie-root-port,id=pcie-root-port-3,port=0x3,addr=0x1.0x3,bus=pcie.0,chassis=4 \ -device virtio-net-pci,mac=9a:5c:50:fc:6e:9d,id=idsubcb0,netdev=idJyDQVf,bus=pcie-root-port-3,addr=0x0 \ -netdev tap,id=idJyDQVf,vhost=on \ -vnc :5 \ -monitor stdio \ -qmp tcp:0:5955,server,nowait \ -rtc base=utc,clock=host,driftfix=slew \ -boot menu=off,order=cdn,once=c,strict=off \ -enable-kvm \ -device pcie-root-port,id=pcie_extra_root_port_0,multifunction=on,bus=pcie.0,addr=0x3,chassis=5 3.execute blockdev-reopen to change different throttle group {"execute": "qmp_capabilities", "id": "zAbD4B7e"} {"execute": "blockdev-reopen", "arguments": {"options": [{"driver": "throttle", "node-name": "drive_stg2", "file": "qcow2_stg2", "throttle-group": "group2"}]}, "id": "05L43QcB"} Actual results: after step 3 ,the qemu crashed Expected results: qemu should not crash Additional info: It may work after remove iothread ,like as: -device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pcie-root-port-2,addr=0x0 \ Not find this issue on Red Hat Enterprise Linux release 8.5 (Ootpa) 4.18.0-348.el8.x86_64 qemu-kvm-6.0.0-33.module+el8.5.0+13740+349232b6.2.x86_64 But it use different interface: {'execute': 'x-blockdev-reopen', 'arguments': {'driver': 'throttle', 'node-name': 'drive_stg2', 'file': 'qcow2_stg2', 'throttle-group': 'group2'}, 'id': 'hQKhdJ8l'} auto case: python3 ConfigTest.py --testcase=throttle_operation_test.group_move.to_normal --platform=x86_64 --guestname=RHEL.9.0.0 --driveformat=virtio_scsi --clone=no --iothread_scheme=roundrobin --nr_iothreads=2