Hello Powerpc folks,
I encounter an kdump bug, which I bisect and pin commit 174db9e7f775
("powerpc/pseries/pci: Add support of MSI domains to PHB hotplug")
In that case, using Fedora 36 as host, the mentioned commit as the
guest kernel, and virto-block disk, the kdump kernel will hang:
[ 0.000000] Kernel command line: elfcorehdr=0x22c00000
no_timer_check net.ifnames=0 console=tty0 console=hvc0,115200n8
irqpoll maxcpus=1 noirqdistrib reset_devices cgroup_disable=memory
numa=off udev.children-max=2 ehea.use_mcs=0 panic=10
kvm_cma_resv_ratio=0 transparent_hugepage=never novmcoredd
hugetlb_cma=0
...
[ 7.763260] virtio_blk virtio2: 32/0/0 default/read/poll queues
[ 7.771391] virtio_blk virtio2: [vda] 20971520 512-byte logical
blocks (10.7 GB/10.0 GiB)
[ 68.398234] systemd-udevd[187]: virtio2: Worker [190]
processing SEQNUM=1193 is taking a long time
[ 188.398258] systemd-udevd[187]: virtio2: Worker [190]
processing SEQNUM=1193 killed
During my test, I found that in very rare cases, the kdump can success
(I guess it may be due to the cpu id). And if using either maxcpus=2
or using scsi-disk, then kdump can also success. And before the
mentioned commit, kdump can also success.
The attachment contains the xml to reproduce that bug.
Do you have any ideas?
Thanks
<domain type="kvm">
<name>rhel9</name>
<uuid>6266c1c1-1e74-4046-b959-33d94877b387</uuid>
<metadata>
<libosinfo:libosinfo xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0";>
<libosinfo:os id="http://redhat.com/rhel/8-unknown"/>
</libosinfo:libosinfo>
</metadata>
<memory unit="KiB">16777216</memory>
<currentMemory unit="KiB">16777216</currentMemory>
<vcpu placement="static">16</vcpu>
<os>
<type arch="ppc64le" machine="pseries-rhel8.6.0">hvm</type>
<boot dev="hd"/>
</os>
<cpu mode="custom" match="exact" check="none">
<model fallback="forbid">POWER9</model>
</cpu>
<clock offset="utc"/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<devices>
<emulator>/usr/libexec/qemu-kvm</emulator>
<disk type="file" device="disk">
<driver name="qemu" type="qcow2"/>
<source file="/var/lib/libvirt/images/rhel-guest-image-9.1-20220701.0.ppc64le.qcow2"/>
<target dev="vda" bus="virtio"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x04" function="0x0"/>
</disk>
<controller type="usb" index="0" model="qemu-xhci" ports="15">
<address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x0"/>
</controller>
<controller type="pci" index="0" model="pci-root">
<model name="spapr-pci-host-bridge"/>
<target index="0"/>
</controller>
<controller type="virtio-serial" index="0">
<address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x0"/>
</controller>
<interface type="network">
<mac address="52:54:00:74:c9:50"/>
<source network="default"/>
<model type="virtio"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x0"/>
</interface>
<serial type="pty">
<target type="spapr-vio-serial" port="0">
<model name="spapr-vty"/>
</target>
<address type="spapr-vio" reg="0x30000000"/>
</serial>
<console type="pty">
<target type="serial" port="0"/>
<address type="spapr-vio" reg="0x30000000"/>
</console>
<channel type="unix">
<target type="virtio" name="org.qemu.guest_agent.0"/>
<address type="virtio-serial" controller="0" bus="0" port="1"/>
</channel>
<input type="tablet" bus="usb">
<address type="usb" bus="0" port="1"/>
</input>
<input type="keyboard" bus="usb">
<address type="usb" bus="0" port="2"/>
</input>
<tpm model="tpm-spapr">
<backend type="emulator" version="2.0"/>
<address type="spapr-vio" reg="0x00004000"/>
</tpm>
<graphics type="vnc" port="-1" autoport="yes">
<listen type="address"/>
</graphics>
<audio id="1" type="none"/>
<video>
<model type="vga" vram="16384" heads="1" primary="yes"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x07" function="0x0"/>
</video>
<memballoon model="virtio">
<address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x0"/>
</memballoon>
<rng model="virtio">
<backend model="random">/dev/urandom</backend>
<address type="pci" domain="0x0000" bus="0x00" slot="0x06" function="0x0"/>
</rng>
<panic model="pseries"/>
</devices>
</domain>
