Issue 27744: test_aes_cbc is blocking x86-64 Ubuntu 15.10 Skylake CPU 3.x for a…

Issue 27744: test_aes_cbc is blocking x86-64 Ubuntu 15.10 Skylake CPU 3.x for a while. Require Kernel 4.3+ for now

Lib/test/test_socket.py

@@ -5378,7 +5378,9 @@ class LinuxKernelCryptoAPI(unittest.TestCase):
                 op.sendall(b"what do ya want for nothing?")
                 self.assertEqual(op.recv(512), expected)
 
-    @support.requires_linux_version(3, 19)
+    # Although it should work with 3.19 and newer the test blocks on
+    # Ubuntu 15.10 with Kernel 4.2.0-19.
+    @support.requires_linux_version(4, 3)
     def test_aes_cbc(self):
         key = bytes.fromhex('06a9214036b8a15b512e03d534120006')
         iv = bytes.fromhex('3dafba429d9eb430b422da802c9fac41')
@@ -5419,7 +5421,7 @@ class LinuxKernelCryptoAPI(unittest.TestCase):
             self.assertEqual(len(dec), msglen * multiplier)
             self.assertEqual(dec, msg * multiplier)
 
-    @support.requires_linux_version(3, 19)
+    @support.requires_linux_version(4, 3)  # see test_aes_cbc
     def test_aead_aes_gcm(self):
         key = bytes.fromhex('c939cc13397c1d37de6ae0e1cb7c423c')
         iv = bytes.fromhex('b3d8cc017cbb89b39e0f67e2')
@@ -5483,7 +5485,7 @@ class LinuxKernelCryptoAPI(unittest.TestCase):
                 res = op.recv(len(msg))
                 self.assertEqual(plain, res[assoclen:-taglen])
 
-    @support.requires_linux_version(3, 19)
+    @support.requires_linux_version(4, 3)  # see test_aes_cbc
     def test_drbg_pr_sha256(self):
         # deterministic random bit generator, prediction resistance, sha256
         with self.create_alg('rng', 'drbg_pr_sha256') as algo: