- Process (a) is blocked in read on a socket waiting on data.
- Process (b) is blocked in shutdown() on a socket waiting on (a).
- Process (c) delivers a signal to (b) interrupting its wait.
When the signal is delivered, the kernel panics as sblock() fails in
sorflush(). Even if it didn't panic, shutdown() would block potentially
indefinitely waiting for recv() to succeeded. Fixes to follow.
Reported by: Jos Backus <jos at catnook dot com>