[PPC64LE buildbots] test_socket: VSOCK testStream(): recv fails with EACCES on Fedora 41

[encukou]

Example of failure: https://buildbot.python.org/#/builders/1467/builds/303/steps/6/logs/stdio

Traceback (most recent call last):
  File ".../Lib/test/test_socket.py", line 550, in testStream
    msg = self.conn.recv(1024)
PermissionError: [Errno 13] Permission denied

See also: #119461 (cc @vstinner)

Linked PRs

• gh-128116: Skip test_socket VSOCK testStream() on PermissionError #128120
• [3.13] gh-128116: Skip test_socket VSOCK testStream() on PermissionError (GH-128120) #128123
• [3.12] gh-128116: Skip test_socket VSOCK testStream() on PermissionError (GH-128120) #128124

[vstinner]

I failed to reproduce the issue. I connected to the PPC64LE Fedora Stable buildbot, I built Python and ran:

./python -m test test_socket -m testStream -v

I tried as the vstinner user, and as the buildbot user: the test succeed in both cases.

[vstinner]

Some logs on the buildbot:

vstinner@localhost:~/python/3.13$ ls -l /dev/vsock
crw-rw-rw-. 1 root root 10, 60 Dec 18 21:14 /dev/vsock

vstinner@localhost:~/python/3.13$ cat x.py 
import socket
import fcntl
import struct


def get_cid():
    if fcntl is None:
        print("a")
        return None
    if not hasattr(socket, 'IOCTL_VM_SOCKETS_GET_LOCAL_CID'):
        print("b")
        return None
    try:
        with open("/dev/vsock", "rb") as f:
            r = fcntl.ioctl(f, socket.IOCTL_VM_SOCKETS_GET_LOCAL_CID, "    ")
    except OSError as exc:
        print("c", exc)
        return None
    else:
        return struct.unpack("I", r)[0]

print("CID", get_cid())

vstinner@localhost:~/python/3.13$ ./python x.py 
CID 4294967295

[vstinner]

Last success, Fedora 40 with glibc 2.39: https://buildbot.python.org/#/builders/90/builds/5363/

os.uname: posix.uname_result(sysname='Linux', nodename='localhost.localdomain', release='5.8.17-200.fc32.ppc64le', version='#1 SMP Thu Oct 29 18:00:08 UTC 2020', machine='ppc64le')
platform.freedesktop_os_release[NAME]: Fedora Linux
platform.freedesktop_os_release[VERSION]: 40 (Server Edition)
platform.libc_ver: glibc 2.39
platform.platform: Linux-5.8.17-200.fc32.ppc64le-ppc64le-with-glibc2.39

First error, Fedora 41 with glibc 2.40: https://buildbot.python.org/#/builders/90/builds/5364/

os.uname: posix.uname_result(sysname='Linux', nodename='localhost.localdomain', release='5.8.17-200.fc32.ppc64le', version='#1 SMP Thu Oct 29 18:00:08 UTC 2020', machine='ppc64le')
platform.freedesktop_os_release[NAME]: Fedora Linux
platform.freedesktop_os_release[VERSION]: 41 (Server Edition)
platform.libc_ver: glibc 2.40
platform.platform: Linux-5.8.17-200.fc32.ppc64le-ppc64le-with-glibc2.40

[vstinner]

I wrote PR gh-128120 to skip the test is recv() fails with EACCESS.

[vstinner]

Fixed by change cbfe302. The backport to 3.13 will follow.