Arch Linux

System can lock on poweroff at ::Sending SIGTERM To Processes [BUSY], if some ELF binary located on non-root partition is still running

Description:
I have some ELF program on non-root partition (ntfs-3g) that I autostart in Gnome. It not gets killed, when gdm stops. What program, doesn't matter because it can be reproduced by copying /bin/sleep to another partition and starting it from there.

When I poweroff, it prints to console that it can't unmount that partition. The last message is:
::Sending SIGTERM To Processes [BUSY]

and then it locks: I can switch terminals with ctrl+alt+F?, but I can't login because getty (?) already died.

I disabled gdm, and starting "sleep" from tty1, but the problem is still there.
I don't know if it's important, but the partition has NTFS.

If some program wasn't started from that partition, but has opened files on it (or cwd), unmounting fails, but poweroff not locks.

Additional info:
reproduced on VBox, see screenshot:
http://img189.imageshack.us/img189/3420/poweroff.png
last ran "pacman -Suy" on March 3

Steps to reproduce:
* add another partition to /etc/fstab (executable flag must be on)
* copy /bin/sleep to it
* login to tty1
* start "sleep". In my case the command is: nohup /media/USBHDD/3/sleep 5000&
* poweroff