[libvirt] [PATCH 5/5] snapshot: Add tests of virsh -c test:///default snapshot*

[Roman Bogorodskiy]

  Eric Blake wrote:

> Had this been in place earlier, I would have avoided the bugs in
> commit 0baf6945 and 55c2ab3e. Writing the test required me to extend
> the power of virsh - creating enough snapshots to cause fanout
> requires enough input in a single session that adding comments and
> markers makes it easier to check that output is correct. It's still a
> bit odd that with test:///default, reverting to a snapshot changes the
> domain from running to paused (possibly a bug in how the test driver
> copied from the qemu driver) - but the important part is that the test
> is reproducible, and any future tweaks we make to snapshot code have
> less chance of breaking successful command sequences.
> 
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---
>  tests/Makefile.am    |   3 +-
>  tests/virsh-snapshot | 212 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 214 insertions(+), 1 deletion(-)
>  create mode 100755 tests/virsh-snapshot

Hi,

I noticed this test is failing for me:

$ ./tests/virsh-snapshot
expr: not a decimal number: '      29'
Bus error (core dumped)
cmp: EOF on out.cooked
exp err differ: char 8, line 1
$

(lldb) target create "tools/.libs/virsh" --core "/tmp/virsh_13727_0.core"
Core file '/tmp/virsh_13727_0.core' (x86_64) was loaded.
(lldb) bt
* thread #1, name = 'virsh', stop reason = signal SIGBUS
  * frame #0: 0x00000008013984bf libvirt.so.0`virDomainMomentForEachChild(moment=0x0000000802aaea10, iter=(libvirt.so.0`virDomainMomentActOnDescendant at virdomainmomentobjlist.c:80), data=0x00007fffffffdb30) at virdomainmomentobjlist.c:62
    frame #1: 0x000000080139854f libvirt.so.0`virDomainMomentForEachDescendant(moment=0x0000000802aaea10, iter=(libvirt.so.0`testDomainSnapshotDiscardAll at test_driver.c:6445), data=0x00007fffffffdcf0) at virdomainmomentobjlist.c:105
    frame #2: 0x00000008013985c5 libvirt.so.0`virDomainMomentActOnDescendant(payload=0x0000000802aaea10, name=0x00000008010fe488, data=0x00007fffffffdc10) at virdomainmomentobjlist.c:85
    frame #3: 0x00000008013984e2 libvirt.so.0`virDomainMomentForEachChild(moment=0x0000000802aae200, iter=(libvirt.so.0`virDomainMomentActOnDescendant at virdomainmomentobjlist.c:80), data=0x00007fffffffdc10) at virdomainmomentobjlist.c:63
    frame #4: 0x000000080139854f libvirt.so.0`virDomainMomentForEachDescendant(moment=0x0000000802aae200, iter=(libvirt.so.0`testDomainSnapshotDiscardAll at test_driver.c:6445), data=0x00007fffffffdcf0) at virdomainmomentobjlist.c:105
    frame #5: 0x000000080144bb2a libvirt.so.0`testDomainSnapshotDelete(snapshot=0x0000000802b46960, flags=4) at test_driver.c:6506
    frame #6: 0x000000080156129e libvirt.so.0`virDomainSnapshotDelete(snapshot=0x0000000802b46960, flags=4) at libvirt-domain-snapshot.c:1047
    frame #7: 0x00000000010a5c4d virsh`cmdSnapshotDelete(ctl=0x00007fffffffdf48, cmd=0x0000000802b39520) at virsh-snapshot.c:1921
    frame #8: 0x00000000010af700 virsh`vshCommandRun(ctl=0x00007fffffffdf48, cmd=0x0000000802b39520) at vsh.c:1335
    frame #9: 0x00000000010698b2 virsh`main(argc=4, argv=0x00007fffffffe088) at virsh.c:920
    frame #10: 0x000000000106910b virsh`_start(ap=<unavailable>, cleanup=<unavailable>) at crt1.c:76
(lldb) fr s 0
frame #0: 0x00000008013984bf libvirt.so.0`virDomainMomentForEachChild(moment=0x0000000802aaea10, iter=(libvirt.so.0`virDomainMomentActOnDescendant at virdomainmomentobjlist.c:80), data=0x00007fffffffdb30) at virdomainmomentobjlist.c:62
   59       virDomainMomentObjPtr child = moment->first_child;
   60  
   61       while (child) {
-> 62           virDomainMomentObjPtr next = child->sibling;
   63           (iter)(child, child->def->name, data);
   64           child = next;
   65       }
(lldb) p child
(virDomainMomentObjPtr) $0 = 0x5a5a5a5a5a5a5a5a
(lldb) fr s 6
frame #6: 0x000000080156129e libvirt.so.0`virDomainSnapshotDelete(snapshot=0x0000000802b46960, flags=4) at libvirt-domain-snapshot.c:1047
   1044                              error);
   1045
   1046     if (conn->driver->domainSnapshotDelete) {
-> 1047         int ret = conn->driver->domainSnapshotDelete(snapshot, flags);
   1048         if (ret < 0)
   1049             goto error;
   1050         return ret;
(lldb) p snapshot->name
(char *) $1 = 0x00000008010fe3e0 "s6"
(lldb) 

I guess 0x5a5a5a5a5a5a5a5a is coming from jemalloc's junk option:

       opt.junk (const char *) r- [--enable-fill]
           Junk filling. If set to “alloc”, each byte of uninitialized
           allocated memory will be initialized to 0xa5. If set to “free”, all
           deallocated memory will be initialized to 0x5a. If set to “true”,
           both allocated and deallocated memory will be initialized, and if
           set to “false”, junk filling be disabled entirely. This is intended
           for debugging and will impact performance negatively. This option
           is “false” by default unless --enable-debug is specified during
           configuration, in which case it is “true” by default.

(from jemalloc(3)).

Roman Bogorodskiy
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