svn commit: r287864 - head/sys/kern

[John Baldwin]

On Wednesday, September 16, 2015 04:40:08 PM John Baldwin wrote:
> Author: jhb
> Date: Wed Sep 16 16:40:07 2015
> New Revision: 287864
> URL: https://svnweb.freebsd.org/changeset/base/287864
> 
> Log:
>   When a process group leader exits, all of the processes in the group are
>   sent SIGHUP and SIGCONT if any of the processes are stopped.  Currently this
>   behavior is triggered for any type of process stop including ptrace() stops
>   and transient stops for single threading during exit() and execve().
>   Thus, if a debugger is attached to a process in a group when the leader
>   exits, the entire group can be HUPed.  Instead, only send the signals if a
>   process in the group is stopped due to SIGSTOP.

In particular, gdb creates a new process group each time it runs a new
process.  If that process forks a child and gdb follows the child, the
child is killed with SIGHUP when the parent exits without this fix.

-- 
John Baldwin