1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
# Regression test for an nspawn-only systemd re-exec failure that broke D-Bus.
#
# Demonstrates `systemctl show` keeps working on `daemon-reexec`.
#
# Trigger: `systemctl daemon-reexec` issues a D-Bus `Manager.Reexecute`, like
# `switch-to-configuration-ng` on a systemd package change.
#
# Root cause: inside nspawn test containers PID 1 re-send `READY=1` on the
# `NOTIFY_SOCKET` on re-exec. The test driver stopped draining that socket
# after boot, so until drained its receive buffer filled and `systemctl` hung /
# errored `Failed to connect to bus: Transport endpoint is not connected`.
{ ... }:
{
name = "nspawn-daemon-reexec-dbus";
# `containers.<name>` => systemd-nspawn machine (vs `nodes.<name>` => QEMU).
# An empty container boots full systemd + D-Bus, which is all we need.
containers.machine = { };
testScript = # python
''
import re
BUS_BROKEN = re.compile(
r"Transport endpoint is not connected|Failed to connect to bus"
)
# Without the fix the notify socket's receive buffer fills after 10
# undrained `READY=1` resends, so PID 1 blocks then.
REEXECS = 10
def bus_broken():
"""Whether the in-container D-Bus is unusable. A broken bus prints a
transport error or hangs until `timeout` kills it (status 124); both
count as broken."""
status, out = machine.execute(
"timeout 10 systemctl show -p ActiveState --value "
"multi-user.target 2>&1",
check_return=False,
timeout=20,
)
return status != 0 or bool(BUS_BROKEN.search(out)), status, out
machine.start()
machine.wait_for_unit("multi-user.target", timeout=120)
# Pre-reexec sanity: the bus works and shows no break.
broken, status, out = bus_broken()
assert not broken, (
f"bus already broken before any reexec: status={status} out={out!r}"
)
machine.log(f"pre-reexec sanity OK: {out.strip()!r}")
broke_at = None
for i in range(1, REEXECS + 1):
# The same D-Bus Manager.Reexecute that switch-to-configuration issues
# on a systemd change.
machine.execute(
"timeout 30 systemctl daemon-reexec",
check_return=False,
timeout=45,
)
broken, status, out = bus_broken()
machine.log(f"[reexec {i}] status={status} out={out.strip()!r}")
if broken:
broke_at = i
break
assert broke_at is None, (
f"nspawn D-Bus broke after daemon-reexec #{broke_at} of {REEXECS} "
"(systemctl hung or returned a bus transport error). The re-exec'd "
"PID 1 never finished re-initialising -- the test driver stopped "
"draining the notify socket, so PID 1's READY=1 resend blocked. "
"Never observed on QEMU."
)
'';
}
|
