Message 70561 - Python tracker

Message70561

Author	loewis
Recipients	amaury.forgeotdarc, benjamin.peterson, loewis, pitrou
Date	2008-08-01.15:45:38
SpamBayes Score	0.009899292
Marked as misclassified	No
Message-id	<1217605539.5.0.942982690815.issue3476@psf.upfronthosting.co.za>
In-reply-to

Content
I don't think the proposed patch (file11012) makes it thread-safe, and I believe you cannot get it thread-safe without using thread synchronization. For example, if two threads simultaneously determine that there is still space left (len(b) <= free), they might both write to self._write_buf and self._write_end, and the last writer would win. (In case it isn't clear how this might happen: thread 1 exhausts its Py_Ticker just after checking the size, then thread 2 runs a full .write(), then thread 1 continues filling the buffer)

Content

I don't think the proposed patch (file11012) makes it thread-safe, and I
believe you cannot get it thread-safe without using thread synchronization.

For example, if two threads simultaneously determine that there is still
space left (len(b) <= free), they might both write to self._write_buf
and self._write_end, and the last writer would win. (In case it isn't
clear how this might happen: thread 1 exhausts its Py_Ticker just after
checking the size, then thread 2 runs a full .write(), then thread 1
continues filling the buffer)

History
Date	User	Action	Args
2008-08-01 15:45:39	loewis	set	recipients: + loewis, amaury.forgeotdarc, pitrou, benjamin.peterson
2008-08-01 15:45:39	loewis	set	messageid: <1217605539.5.0.942982690815.issue3476@psf.upfronthosting.co.za>
2008-08-01 15:45:38	loewis	link	issue3476 messages
2008-08-01 15:45:38	loewis	create