[libvirt] [PATCH 00/16] snapshot refactoring (incremental backup saga)

[John Ferlan]

On 3/22/19 7:04 AM, Andrea Bolognani wrote:
> On Fri, 2019-03-22 at 06:50 -0400, John Ferlan wrote:
>> On 3/22/19 4:46 AM, Andrea Bolognani wrote:
>>> This causes libvirtd to crash at startup on my machine.
>>>
>>> Have a backtrace:
>>>
>>>   Thread 19 (Thread 0x7fffaa4e0700 (LWP 31651)):
>>>   #0  0x00007ffff72ecd31 in open64 () from /lib64/libc.so.6
>>>   #1  0x00007ffff727d3f6 in _IO_file_open () from /lib64/libc.so.6
>>>   #2  0x00007ffff727d5ad in __GI__IO_file_fopen () from /lib64/libc.so.6
>>>   #3  0x00007ffff727132d in __fopen_internal () from /lib64/libc.so.6
>>>   #4  0x00007ffff71199d8 in ?? () from /lib64/libudev.so.1
>>>   #5  0x00007ffff71146dd in ?? () from /lib64/libudev.so.1
>>>   #6  0x00007ffff71173ed in ?? () from /lib64/libudev.so.1
>>>   #7  0x00007ffff71179d9 in ?? () from /lib64/libudev.so.1
>>>   #8  0x00007ffff710be77 in udev_device_get_property_value () from /lib64/libudev.so.1
>>>   #9  0x00007fffc2e8a3ef in udevGetDeviceProperty (udev_device=udev_device at entry=0x7fff900606e0, property_key=property_key at entry=0x7fffc2ea3504 "DRIVER") at node_device/node_device_udev.c:140
>>>   #10 0x00007fffc2e8a459 in udevGetStringProperty (udev_device=udev_device at entry=0x7fff900606e0, property_key=property_key at entry=0x7fffc2ea3504 "DRIVER", value=0x7fff900f98d8) at node_device/node_device_udev.c:154
>>>   #11 0x00007fffc2e8b3ad in udevAddOneDevice (device=device at entry=0x7fff900606e0) at node_device/node_device_udev.c:1369
>>>   #12 0x00007fffc2e8d27e in udevProcessDeviceListEntry (list_entry=0x7fff9004f350, udev=0x7fff98120f00) at node_device/node_device_udev.c:1435
>>>   #13 udevEnumerateDevices (udev=0x7fff98120f00) at node_device/node_device_udev.c:1489
>>>   #14 nodeStateInitializeEnumerate (opaque=0x7fff98120f00) at node_device/node_device_udev.c:1798
>>>   #15 0x00007ffff7c5a2c2 in virThreadHelper (data=<optimized out>) at util/virthread.c:206
>>>   #16 0x00007ffff740d58e in start_thread () from /lib64/libpthread.so.0
>>>   #17 0x00007ffff72fc6a3 in clone () from /lib64/libc.so.6
>>
>> Very strange - I don't recall the patches touching any of the
>> virnodedeviceobj* code. Is it possible to bisect to something after the
>> below?
>>
>> Although there were changes by Nikolay right at the top of tree that
>> did... Can you go back to top, revert Nikolay's changes and see if that
>> does it?  You will need Michal's change to virDomainMomentAssignDef.
> 
> Michal's patch seems to do the trick: I built from 5e752513d802
> and the daemon starts fine even when I have guests with snapshots.
> 

Great... That was my first instinct, but would have expected to see this
thread causing the issue not the udev one:

  Thread 17 (Thread 0x7fffab4e2700 (LWP 31607)):
  #0  0x00007ffff7cc1c85 in virDomainMomentAssignDef
(moments=0x7fff981af8a0, def=def at entry=0x7fff98227870) at
conf/virdomainmomentobjlist.c:230

gotta go check the coffee pot - I hope it wasn't decaf this morning!

Tks -

John