Bug 1937287

Created attachment 1762239 [details]
backtrace

The problem is in the format string used to construct a numeric gvariant. Unfortunately the code path isn't covered by tests.

Glib also reports:


(process:3561615): GLib-CRITICAL **: 14:32:08.663: 'llu' does not have a valid GVariant format string as a prefix

(process:3561615): GLib-CRITICAL **: 14:32:08.663: g_variant_new_va: assertion 'valid_format_string (format_string, !endptr, NULL)' failed

Fixed upstream by:

commit 7b8f78a3afcb51f74cc81b69226a3c49a49f0b9b
Author: Peter Krempa <pkrempa>
Date:   Wed Mar 10 14:37:56 2021 +0100

    virsystemdtest: Call at least one virSystemdCreateMachine with 'maxthreads' > 0
    
    There was a bug in the code adding TasksMax property. It remained
    undetected because all tests used '0' for @maxthreads.
    
    Signed-off-by: Peter Krempa <pkrempa>
    Reviewed-by: Pavel Hrdina <phrdina>

commit 07c6e493b2466c47401b6eb8a3f9b7d2d20df83e
Author: Peter Krempa <pkrempa>
Date:   Wed Mar 10 14:33:06 2021 +0100

    virSystemdCreateMachine: Use proper format string for uint64_t when constructing gvariant
    
    g_variant_new_parsed uses '%t' for a uint64_t rather than printf-like
    %llu. Additionally ensure that the passed value is a uint64_t since the
    argument used is a 'unsigned int'.
    
    Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1937287
    Fixes: bf5f2ed09c2
    Signed-off-by: Peter Krempa <pkrempa>
    Reviewed-by: Pavel Hrdina <phrdina>

Exception approved in review meeting on 12 Mar 2021.

Verified on: libvirt-7.0.0-9.module+el8.4.0+10326+5e50a3b6.x86_64
Result: PASS

Cgroup1 ENV:
[root@lenovo-sr630-10 ~]# grep -i ^max_threads  /etc/libvirt/qemu.conf
max_threads_per_process = 2 
[root@lenovo-sr630-10 ~]# systemctl restart libvirtd
[root@lenovo-sr630-10 ~]# virsh start gls
error: Failed to start domain 'gls'
error: internal error: process exited while connecting to monitor: qemu: qemu_thread_create: Resource temporarily unavailable

[root@lenovo-sr630-10 ~]# grep -i ^max_threads  /etc/libvirt/qemu.conf
max_threads_per_process = 128 
[root@lenovo-sr630-10 ~]# systemctl restart libvirtd
[root@lenovo-sr630-10 ~]# virsh start gls
Domain 'gls' started

[root@lenovo-sr630-10 ~]# cat /sys/fs/cgroup/pids/machine.slice/machine-qemu\\x2d1\\x2dgls.scope/pids.max 
128


[root@lenovo-sr630-10 ~]# grep -i ^max_threads  /etc/libvirt/qemu.conf
max_threads_per_process = 99999 
[root@lenovo-sr630-10 ~]# systemctl restart libvirtd
[root@lenovo-sr630-10 ~]# virsh start gls
Domain 'gls' started

[root@lenovo-sr630-10 ~]# cat /sys/fs/cgroup/pids/machine.slice/machine-qemu\\x2d1\\x2dgls.scope/pids.max 
99999

Cgroup2 ENV:
[root@dell-per740-01 ~]# grep -i ^max_threads  /etc/libvirt/qemu.conf
max_threads_per_process = 100 
[root@dell-per740-01 ~]# systemctl restart libvirtd
[root@dell-per740-01 ~]# virsh start vm1
Domain 'vm1' started

[root@dell-per740-01 ~]# grep -i ^max_threads  /etc/libvirt/qemu.conf
max_threads_per_process = 2 
[root@dell-per740-01 ~]# systemctl restart libvirtd
[root@dell-per740-01 ~]# virsh start vm1
error: Failed to start domain 'vm1'
error: internal error: process exited while connecting to monitor: qemu: qemu_thread_create: Resource temporarily unavailable

[root@dell-per740-01 ~]# grep -i ^max_threads  /etc/libvirt/qemu.conf
max_threads_per_process = 99999 
[root@dell-per740-01 ~]# systemctl restart libvirtd
[root@dell-per740-01 ~]# virsh start vm1
Domain 'vm1' started

[root@dell-per740-01 ~]# cat /sys/fs/cgroup/machine.slice/machine-qemu\\x2d1\\x2dvm1.scope/pids.max 
99999

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 (virt:av bug fix and enhancement update), 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-2021:2098