This report relates to rdesktop 1.6.0 (build 1.6.0-2ubuntu2).
My Ubuntu 9.10 (Karmic) 64 bit locked up suddenly (X stopped responding, sound looped, ctrl-alt-F1 didn't work).
Looking at the syslog I saw the following statement (that matches time-wise):
Jan 21 11:10:00 nsh-ubuntu kernel: [10308.902189] rdesktop[9694]: segfault at 1928dac ip 000000000041f637 sp 00007fff74e796b0 error 4 in rdesktop[400000+3a000]
I was working with rdesktop against a Windows Server 2008 Enterprise (6.0.6002 Service Pack 2 Build 6002) and writing a mail in Outlook 2007 (12.0.6514.5000).
I am not able to reproduce the problem.
It seems as though rdesktop segfaults multiple times when hanging my machine. I did not log on to the server multiple times.
Jan 21 11:51:37 nsh-ubuntu kernel: [ 2293.643675] rdesktop[4611]: segfault at 202320c ip 000000000041f637 sp 00007fffe14c37b0 error 4 in rdesktop[400000+3a000]
Jan 21 11:51:48 nsh-ubuntu kernel: [ 2304.021620] rdesktop[4616]: segfault at 111220c ip 000000000041f637 sp 00007fff023f0a40 error 4 in rdesktop[400000+3a000]