[Python-checkins] gh-95243: Mitigate the race condition in testSockName (#96173)
gpshead
webhook-mailer at python.org
Wed Aug 24 21:37:26 EDT 2022
https://github.com/python/cpython/commit/df110126971d0271a977ce10779083b3e335b4da
commit: df110126971d0271a977ce10779083b3e335b4da
branch: main
author: Ross Burton <ross.burton at arm.com>
committer: gpshead <greg at krypto.org>
date: 2022-08-24T18:37:18-07:00
summary:
gh-95243: Mitigate the race condition in testSockName (#96173)
find_unused_port() has an inherent race condition, but we can't use
bind_port() as that uses .getsockname() which this test is exercising.
Try binding to unused ports a few times before failing.
Signed-off-by: Ross Burton <ross.burton at arm.com>
files:
A Misc/NEWS.d/next/Tests/2022-08-22-14-59-42.gh-issue-95243.DeD66V.rst
M Lib/test/test_socket.py
diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index f1b57fc4071..d808f3f62b9 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -1398,10 +1398,21 @@ def testStringToIPv6(self):
def testSockName(self):
# Testing getsockname()
- port = socket_helper.find_unused_port()
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.addCleanup(sock.close)
- sock.bind(("0.0.0.0", port))
+
+ # Since find_unused_port() is inherently subject to race conditions, we
+ # call it a couple times if necessary.
+ for i in itertools.count():
+ port = socket_helper.find_unused_port()
+ try:
+ sock.bind(("0.0.0.0", port))
+ except OSError as e:
+ if e.errno != errno.EADDRINUSE or i == 5:
+ raise
+ else:
+ break
+
name = sock.getsockname()
# XXX(nnorwitz): http://tinyurl.com/os5jz seems to indicate
# it reasonable to get the host's addr in addition to 0.0.0.0.
diff --git a/Misc/NEWS.d/next/Tests/2022-08-22-14-59-42.gh-issue-95243.DeD66V.rst b/Misc/NEWS.d/next/Tests/2022-08-22-14-59-42.gh-issue-95243.DeD66V.rst
new file mode 100644
index 00000000000..a9ca1f8b867
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2022-08-22-14-59-42.gh-issue-95243.DeD66V.rst
@@ -0,0 +1,3 @@
+Mitigate the inherent race condition from using find_unused_port() in
+testSockName() by trying to find an unused port a few times before failing.
+Patch by Ross Burton.
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