571904 - Freezes permanently after start-up when remote IMAP server connection lost

Status: RESOLVED WORKSFORME

(MailNews Core :: Networking: IMAP, defect)

Description

[Brian]

User-Agent:       Mozilla/5.0 (X11; U; Linux x86_64; en-GB; rv:1.9.2.3) Gecko/20100423 Ubuntu/10.04 (lucid) Firefox/3.6.3
Build Identifier: Thunderbird 3.0.4, Copyright (c) 1998-2010 mozilla.org

I use Thunderbird on my Ubuntu 10.04 64-bit desktop. I have a VPN point-to-point  tunnel (tun0) to a remote Ubuntu 10.04 64-bit server. I recently set up a Postfix/Dovecot/Squirrelmail system on the server and have successfully added an IMAP account on my desktop Thunderbird. The server does not have a valid certificate for smtp and each time Thunderbird starts up it complains and I make a non-permanent exception. All worked perfectly until the internet connection with the server was lost. This caused Thunderbird to completely freeze and turn grey. I had to force-quit it and when I restarted it it first showed its normal window with a timer icon and a few seconds later turned grey again. At no time does Thunderbird respond to mouse inputs. I repeated this 3 times.

When the internet connection and VPN tunnel were functioning again I restarted Thunderbird. This time it opened accompanied by the certificate status warning window attempting to get certificate info from the host. All buttons were greyed out. This remained like this for about a minute before the window seemed to blink back into life and the usual "confirm security exception" and "cancel" buttons were usable. I confirm the exception but deselect "permanently". From this point Thunderbird seems to function normally.

With Thunderbird still running normally, I try to reproduce the freeze by manually disconnecting the VPN. This time, when I click on the imap inbox name, Thunderbird produces a dialog saying the connection to server has been lost but continues to work properly. This is what I would expect correct behaviour to be.

I exit Thunderbird and restart it. It opens its main window and freezes and turns grey. There is no certificate warning window this time. Not responding to the mouse. It remains like this for 5 minutes until I force-quit it.

Suspecting this may be related to the certificate check I investigate whether the "permanent exception" selection will avoid the freeze. I restart the VPN. I then start Thunderbird. This time it opens its main window and freezes and turns grey, without showing the certificate window. But after about 60 seconds it regains its colour and shows a "connection to server timed-out" dialog. It now works fine. If I select the imap inbox the certificate window opens and after a few seconds it asks me to confirm the exception. This time I confirm it and select "permanently store this exception".

Now I turn off the VPN again. When I click on the imap inbox name the timer icon appears and after a few seconds a connection to server timed-out dialog appears and all works ok after that. Now I quit Thunderbird and start it up again. This time it opens its main window and does not freeze. It shows it is searching by the bar bottom right and after a few seconds the connection to server timed-out dialog appears. Everything works fine.

To try to reproduce the original problem I open Thunderbird's Certificate Manager and delete the permanent exception I created. Now when I click the imap inbox name the connection timed-out dialog appears after a few seconds but everything works fine, as expected. When I quit Thunderbird and start it up again it opens its main window and freezes completely and greys out. It is again unusable.

Therefore, my speculation is that there is a bug in the certification module whereby if Thunderbird tries to contact an uncertified imap host, that has not been permanently exceptioned, and cannot do so it completely freezes and renders Thunderbird unusable.

This is a serious problem because when it occurs it is not possible to fix it until or use Thunderbird at all, even after a restart, until such time as Thunderbird can connect to the imap host.




Reproducible: Always

Steps to Reproduce:
1. Disconnect route to remote, uncertified IMAP host
2. Start Thunderbird
3.
Actual Results:  
See details.

Expected Results:  
Thuderbird main window opens, completely frozen to mouse input, then greys out and hangs indefinitely.

It should never have greyed out or forzen and should have shown a "connection to server timed-out" dialog instead.

Comment 1

[Wayne Mery (:wsmwk)]

xref bug 484274 unstable internet/mailserver connectivity results in "program not responding" 

but I'm pretty sure this wasn't the only related bug

Comment 2

[Wayne Mery (:wsmwk)]

Brian, can you reproduce this with v3.1?
 http://www.mozillamessaging.com/en-US/thunderbird/early_releases/
And get a stacktrace?
 https://developer.mozilla.org/En/How_to_get_a_stacktrace_for_a_bug_report#Linux

Bug 546429 has a stacktrace ... hang after dialog alert Could not connect to mail server ... the connection was refused" - no cpu

Comment 3

[Brian]

Wayne, I have not done a stacktrace before. The Ubuntu wiki instructions don't work - apt does not recognize thunderbird-3.0-dbg nor 3.1. I did install just -dbg plus the libs but when I run gdb it complains the file /usr/bin/thunderbird-3.0.4/thunderbird is not executable.
I have downloaded 3.1 rc2 but I don't want to replace my 3.0.4 installation.

Comment 4

[Nikolay Shopik]

Brian,
You can just unpack 3.1 rc2 and run, it will not replace you current version installed.

Comment 5

[Brian]

Thanks Nikolay I have done that.

I am running 3.1 now. I have just disabled the VPN and deleted the permanent certificate exception for my remote imap server. I click on the imap inbox name. It tries to connect, timer and progress bar visible, and about half a minute later it stops trying to connect. A banner announcing the connection time-out appears briefly at the bottom right of my screen. There is no certificate search window. That's it, it works fine. No hanging.

I quit Thunderbird and then start it. It starts fine, no freezing. Immediately searches for the missing host and stops after a short time. Another banner announcing the connection time-out. All works, no hangs.

I reconnect the VPN. When I click the imap inbox it immediately brings up the certificate window (titled: "Add Security Exception") as well as a wide banner warning of the lack of valid certificate. I untick "Permanently store..." and click "Confirm...". Then quit Thunderbird and restart it.

This time Thunderbird immediately shows both its main window and the "Add Security Exception" menu. I untick "Permanently..." and click "confirm...". Then, curiously, the same "Add Security" window appears a second time. Again I untick "Permanently" and tick "Confirm" and this time it goes away and Thunderbird appears as normal. All the imap folders work.


So on first inspection this looks like it has solved the 3.0.4 freeze I experienced. Good stuff!

I am not keen on the fleeting banners at the bottom of my screen, however. I would like to see, on the main screen, a message or alert icon whenever an imap connection is not established.

When will the fully tested 3.1 be available? ;)

Comment 6

[Nikolay Shopik]

Current plan was to ship it in early June, but it slipped. Still it may shipped by end of June or early Jule. I'm closing this bug as WFM per your report, if problem will come back in 3.1 feel free to reopen.

Comment 7

[Brian]

WFM is appropriate. Thank you Wayne and Nikolay for your helpful and timely responses. Brian