Memory leak in request readline()

• Key: MODPYTHON-182
• Type: Bug
• Status: Closed
• Resolution: Fixed
• Priority: Major
• Assignee: Jim Gallacher
• Reporter: Jim Gallacher
• Component/s: core
• Affects Version/s: 3.2.x, 3.3.x, 3.2.10
• Fix Version/s: 3.3.1

Description

There is at least one memory leak request.readline(). I'm currently auditing the code so there may well be others.

I think the leak will only occur when the request body is incompletely read with readline, which is likely an unusual corner case. The following demostrates the leak:

Consider a request body consisting of:

'\n'.join([ 'a'*100 for i in xrange(0, 100) ])

and using this handler:


def handler(req):
    # Handler reads 20 lines but request contains 100 lines.
    # Since the body is not completely read, the buffer allocated
    # in requestobject.c req_readline is never freed.
    req.content_type = 'text/plain'
    count = 0
    for i in range(0, 20):
        line = req.readline()
        count += 1

    req.write('ok readline_partial: %d lines read' % count)
    return apache.OK

With this test setup I'm seeing a leak of approx 10k bytes per request.