# A libvirt GDB session with Martin Kletzander

$ debuginfo-install libvirt
$ gdb libvirtd $(pidof libvirtd)
(gdb) b qemuSetupCpusetMems
Breakpoint 1 at 0x7fa786f0a49c: file qemu/qemu_cgroup.c, line 618.
(gdb) c
Continuing.
Detaching after fork from child process 18699.
Detaching after fork from child process 18700.
Detaching after fork from child process 18702.
[Switching to Thread 0x7fa792767700 (LWP 935)]

Breakpoint 1, qemuSetupCgroupPostInit (vm=vm@entry=0x7fa760000b30, nodemask=0x0) at qemu/qemu_cgroup.c:865
865         return qemuSetupCpusetMems(vm, nodemask);
(gdb) print nodemask
$1 = (virBitmapPtr) 0x0
(gdb) s
qemuSetupCpusetMems (vm=<optimized out>, vm=<optimized out>, nodemask=<optimized out>) at qemu/qemu_cgroup.c:618
618         if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPUSET))
(gdb)
qemuSetupCgroupPostInit (vm=vm@entry=0x7fa760000b30, nodemask=0x0) at qemu/qemu_cgroup.c:864
864     {
(gdb)
865         return qemuSetupCpusetMems(vm, nodemask);
(gdb) s
qemuSetupCpusetMems (vm=0x7fa760000b30, vm=0x7fa760000b30, nodemask=0x0) at qemu/qemu_cgroup.c:615
615         char *mem_mask = NULL;
616         int ret = -1;
617
618         if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPUSET))
619             return 0;
620
621         if (virDomainNumatuneMaybeFormatNodeset(vm->def->numatune,
622                                                 nodemask,
(gdb)
623                                                 &mem_mask, -1) < 0)
624             goto cleanup;
625
626         if (mem_mask &&
627             virCgroupSetCpusetMems(priv->cgroup, mem_mask) < 0)
628             goto cleanup;
629
630         ret = 0;
631      cleanup:
632         VIR_FREE(mem_mask);
(gdb) b 626
Breakpoint 2 at 0x7fa786f0a517: file qemu/qemu_cgroup.c, line 626.
(gdb) c
Continuing.

Breakpoint 2, qemuSetupCpusetMems (vm=0xffffffff, vm=0xffffffff, nodemask=0x0) at qemu/qemu_cgroup.c:626
626         if (mem_mask &&
(gdb) print mem_mask
$2 = 0x7fa76c007c50 "0"
(gdb) list
621         if (virDomainNumatuneMaybeFormatNodeset(vm->def->numatune,
622                                                 nodemask,
623                                                 &mem_mask, -1) < 0)
624             goto cleanup;
625
626         if (mem_mask &&
627             virCgroupSetCpusetMems(priv->cgroup, mem_mask) < 0)
628             goto cleanup;
629
630         ret = 0;
(gdb) c
Continuing.