PuTTY bug ssh-stuck-queue

This is a mirror. The primary PuTTY web site can be found here.

summary: SSH data can get stuck in a queue if session throttled
class: bug: This is clearly an actual problem we want fixed.
present-in: 0.58

If an SSH connection is throttled ("frozen"), incoming data can end up stuck in ssh->queued_incoming_data and not processed until more data arrives from the network (or ever, if the socket has closed in the meantime), since that buffer is only examined when new data arrives. In general, queued data may be being processed rather later than it could be.

For instance, cat'ing a large text file might hang, only to resume when a key is pressed (which will result in outgoing and then incoming traffic).

There's been a report that this shows up in real life when receiving lots of data down an SSH-1 connection, where ssh1_throttle() is called.
<OF39FE4940.43DB4418-ONCC257067.000BF4DD-CC257067.000F5220@bnz.co.nz>

Another likely report of this problem:
<4460FE84.10303@bytte.plus.com>

ssh_set_frozen() should probably signal something, but I'm not sure enough of the control flow to know quite what. (This is already done in some places, e.g., ssh_dialog_callback().)

Audit trail for this bug.

If you want to comment on this web site, see the Feedback page.
(last revision of this bug record was at 2006-05-11 23:47:01 +0100)