Trouble killing processes in SysV/AT

[Eric Varsanyi]

In article <468 at micropen> dave at micropen (David F. Carlson) writes:
> [...]  No close should allow a process
>to wait forever on a event that may not come.  Signals (kill -9) are
>delivered when a process in kernel mode re-enters user mode.  However,
>you process is waiting in kernel mode and won't get those signals til
>its done: NEVER! (or until the long sought interrupt allows it's WCHAN
>to go again.

This is only true if the driver has slept with a wakeup priority < PZERO.
If the process sleeps above PZERO a signal will trash the kernel context
and return to the user with a EINTR (Interrupted system call).