[pypy-issue] [issue1238] "bad write retry" from ssl sockets

Ben Darnell tracker at bugs.pypy.org
Sun Aug 19 08:12:39 CEST 2012

New submission from Ben Darnell <ben at bendarnell.com>:

Writing to an SSL socket in pypy (1.9, tested on mac) sometimes fails with a "bad 
write retry" message, when the same code succeeds in cpython.  I believe this is 
because with pypy's GC, objects may be moved around, so the address of a str 
object may change (if I'm wrong on this point please correct me).  In non-blocking 
mode, openssl requires by default that the same buffer be used for repeated write 
calls.  In cpython this can be done by ensuring that the same string object be 
reused (see e.g 
https://github.com/facebook/tornado/blob/master/tornado/iostream.py#L527), but for 
pypy that doesn't work, so the simplest workaround is to disable this sanity check 
by setting SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER on the ssl context.  

Related cpython issue: http://bugs.python.org/issue8240

It's difficult to make a minimal test case since the bug depends on both socket 
buffering and garbage collection, but 
seems to trigger it reliably.

messages: 4658
nosy: bdarnell, pypy-issue
priority: bug
status: unread
title: "bad write retry" from ssl sockets

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