Hi Andrew, I was playing with kexec+kdump and ran into this on 2.6.10-mm1. I have seen similar behaviour on 2.6.10. I am using a 4-way P-III machine. I have a module which tries gets same spinlock twice. When I try to "insmod" this module, my system hangs. All my windows froze, no more new logins, console froze, doesn't respond to sysrq. I wasn't expecting a system hang. Why ? Ideas ? Here is the code. Thanks, Badari