Re: [PULL 13/14] ui: fix crash when there are no active_console

[Daniel P . Berrangé]

On Tue, Sep 12, 2023 at 02:00:46PM +0300, Michael Tokarev wrote:
> 12.09.2023 13:46, marcandre.lureau@redhat.com пишет:
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> > 
> > Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
> > 0x0000555555888630 in dpy_ui_info_supported (con=0x0) at ../ui/console.c:812
> > 812     return con->hw_ops->ui_info != NULL;
> > (gdb) bt
> > #0  0x0000555555888630 in dpy_ui_info_supported (con=0x0) at 
> > ../ui/console.c:812
> > #1  0x00005555558a44b1 in protocol_client_msg (vs=0x5555578c76c0, 
> > data=0x5555581e93f0 <incomplete sequence \373>, len=24) at ../ui/vnc.c:2585
> > #2  0x00005555558a19ac in vnc_client_read (vs=0x5555578c76c0) at 
> > ../ui/vnc.c:1607
> > #3  0x00005555558a1ac2 in vnc_client_io (ioc=0x5555581eb0e0, 
> > condition=G_IO_IN, opaque=0x5555578c76c0) at ../ui/vnc.c:1635
> > 
> > Fixes:
> > https://issues.redhat.com/browse/RHEL-2600
> 
> FWIW, this link does not work for me (requires auth).

This particular bug is marked as Red Hat employee access only, so
should be dropped from the commit message.

FWIW, it says in terms of reproducability

Steps to reproduce
1. Boot up guest, but only add vnc device and without graphics device
/usr/libexec/qemu-kvm \
-name guest=gg \
-machine pc-q35-rhel8.6.0,kernel_irqchip=split \
-cpu host \
-m 8192 \
-smp 4,maxcpus=4,cores=2,threads=1,dies=1,sockets=2  \
-nodefaults \
-boot menu=on \
-device pcie-root-port,port=16,chassis=1,id=pci.1,bus=pcie.0,addr=0x2 \
-blockdev 
'\{"driver":"file","filename":"/home/kvm_autotest_root/images/rhel890-64-virtio-scsi.qcow2","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}'
 \
-blockdev 
'\{"node-name":"libvirt-1-format","read-only":false,"driver":"qcow2","file":"libvirt-1-storage","backing":null}'
 \
-device 
virtio-blk-pci,bus=pci.1,addr=0x0,drive=libvirt-1-format,id=virtio-disk0 \
-enable-kvm \
-monitor stdio \
-vnc :0 \

2. Try to connect this guest
remote-viewer vnc://10.73.210.78:5900

3. About 10 seconds to trigger qemu core dump.


The trigger appears to be the lack of any VGA device hardware
present, despite having VNC enabled.

With regards,
Daniel
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