semantic: 0.159 network: 0.142 device: 0.088 other: 0.080 socket: 0.078 vnc: 0.076 graphic: 0.074 performance: 0.062 PID: 0.052 permissions: 0.050 debug: 0.049 files: 0.041 boot: 0.034 KVM: 0.016 debug: 0.548 PID: 0.090 files: 0.087 other: 0.061 performance: 0.041 network: 0.037 boot: 0.032 device: 0.032 semantic: 0.017 socket: 0.016 graphic: 0.013 vnc: 0.010 permissions: 0.010 KVM: 0.007 signal mask not reset on exec Seen in qemu-1.0 under 12.04, but AFAICT from current git it hasn't changed. ./main-loop.c:qemu_signal_init blocks SIGALRM so it can be handled via signalfd. ./net/tap.c:launch_script does not reset the signal mask before the execv() call, and signal masks are inherited. So the script is run with SIGALRM blocked (as can be seen in /proc/$$/status, "SigBlk: 0000000000002000"). One reasonable example of where this bites is an interface up script that calls ping with a timeout to give things a chance to settle down before continuing, but abort if this doesn't happen within a reasonable time). Since ping uses SIGALRM for the timeout, this now never terminates. qemu-0.14 didn't block SIGALRM, so such scripts worked fine there. Triaging old bug tickets... can you still reproduce this issue with the latest version of QEMU? Or could we close this ticket nowadays? [Expired for QEMU because there has been no activity for 60 days.]