On Fri, Apr 11, 2014 at 05:40:25AM +0000, Santhosh Kokala wrote: This is because we failed to start the process mentioned in the error message. Unfortunately, we're not doing much of a debugging in that area of the code, so there isn't much information to see even if you have debug messages turned on. Basically, this means capng_apply(3) failed with -1, but that's all we know now. You can try running libvirt under gdb, set breakpoint in capng_apply and ... see what you can get from that. Unfortunately that's all I know about capng, maybe someone else will provide better insight. The only way this is a bug in libvirt is if we're for example compiled with libcap-ng that provides PR_CAPBSET_DROP, but the kernel doesn't somehow. Otherwise I see no patch changing anything in the capng area of the code between 1.1.2 and current HEAD. Martin