Firefox 3.0 freezes waiting to resolve safebrowsing-cache.google.com in DNS

My current daytime setup is for various reasons a Windows XP installation with Ubuntu Jaunty running inside VirtualBox. I use Microsoft Windows for Outlook, SQL Navigator and some web browsing while using the Linux installation for development. This morning I started Firefox in Windows XP, changed focus to VirtualBox or some other window, and when I returned to Firefox it was frozen. I followed the standard Windows trouble-shooting procedure: reboot and get a coffee. When I was logged in again in both Windows and Ubuntu I got the same issue with Firefox in Linux. WTF?

At least I have the tools in Ubuntu to debug this issue. This is a simplified version and approximate order of what I did.

First, create ~/.gdbinit to make GDB a tad more user-friendly:

set pagination off
set radix 16
set print pretty
set history save on

Second, add ddebs.ubuntu.com to /etc/apt/sources.list:

deb //ddebs.ubuntu.com/ jaunty main restricted universe multiverse
deb //ddebs.ubuntu.com/ jaunty-updates main restricted universe multiverse
deb //ddebs.ubuntu.com/ jaunty-security main restricted universe multiverse
deb //ddebs.ubuntu.com/ jaunty-proposed main restricted universe multiverse

Install some debug symbols:

sudo apt-get install firefox-3.0-dbgsym libnspr4-0d-dbgsym xulrunner-1.9-dbgsym

Debugging time!

$ gdb `which firefox` `pidof firefox`

(gdb) thread apply all bt

Thread 2 (Thread 0xb08eab90 (LWP 4253)):

#9  0xb7e16c7f in getaddrinfo () from /lib/tls/i686/cmov/libc.so.6
#10 0xb7c8d739 in PR_GetAddrInfoByName (hostname=0xbc01ff4 “safebrowsing-cache.google.com”, af=0x0, flags=0x8020) at prnetdb.c:2026
#11 0xb7267940 in nsHostResolver::ThreadFunc (arg=0x92d9fd8) at nsHostResolver.cpp:697

Thread 1 (Thread 0xb7d4b6d0 (LWP 4243)):
#0  0xb8003422 in __kernel_vsyscall ()
#1  0xb7fe30e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb7c94ed9 in PR_WaitCondVar (cvar=0xcd1ebf8, timeout=0xffffffff) at ptsynch.c:405
#3  0xb7c94f57 in PR_Wait (mon=0xd47d178, timeout=0xffffffff) at ptsynch.c:584
#4  0xb726621b in nsDNSService::Resolve (this=0x92d4b00, hostname=@0xabaf730, flags=<value optimized out>, result=0xbff19ac0) at nsDNSService2.cpp:49

So, we have a thread that is resolving “safebrowsing-cache.google.com” and another thread waiting for this hostname to be resolved. Could this be an issue?

Back at the command line, is there an issue with this domain name? Checking on my local computer:

$ host safebrowsing-cache.google.com
;; connection timed out; no servers could be reached

Trouble at Google? I must confirm that, so I login to one of my servers and run the same command:

$ host safebrowsing-cache.google.com
;; Truncated, retrying in TCP mode.
safebrowsing-cache.google.com is an alias for safebrowsing.cache.l.google.com.
safebrowsing.cache.l.google.com has address 74.125.10.92

Works fine, but what does Truncated, retrying in TCP mode mean? I will investigate that later.

Apparently the company firewall is unable to resolve this domain name, at least for the time being. Google Safe Browsing is built into Firefox 3, so how do I disable it? I looked in about:config and yes, there was a setting called browser.safebrowsing.enabled set to true. I set it to false and… Firefox still froze. Looking at about:config again, I found browser.safebrowsing.malware.enabled and set that one to false as well. Now I am able to write this blog post!

Disabling these configuration options is only curing the symptoms, not the disease. But can I cure an enterprise DNS server that fails to handle truncated responses? I doubt it.

Solved problems installing a graphics card in a Windows 2003 Server

My computer troubles did not stop with the RAM failure on my laptop.

The next issue was a server upgrade at work. We needed to put a graphics card into a server. (Don’t ask why!) The HP ProLiant ML110 G5 server has a built-in Matrox G200e (with 8 megabytes of RAM) and I installed a  PNY Quadro NVS 290 with PCI-Express x1 interface. (The server only has PCI-Express up to x8, not x16 as 99% of all graphics cards require!)

It was not possible to disable the integrated graphics in BIOS so we only disabled it in the Windows Server 2003 Device Manager. So far so good! The weird thing was that Remote Desktop stopped working. It took me embarassingly long to find the relevant message in the Event Viewer: SystemRootSystem32RDPDD.dll failed to load. Once I found that message it didn’t take long to find and try the suggested solution and it worked at last!