How to kick process out of uninterruptible sleep?

Wed Nov 9 19:56:00 GMT 2016

Il 2016-11-09, Frank Ch. Eigler <fche@redhat.com> ha scritto:
> Riccardo Murri <riccardo.murri@uzh.ch> writes:
>
>> [...]  I have a server where a process got stuck in "uninterruptible
>> sleep" during NFS access.  [...]  `ps -O wchan` shows it's stuck in
>> `nfs_wait_bit_uninterruptible` [...]
>
> AFAIK, a "kill -9" nukes such processes from userspace.  

Apparently not:

# ps -O wchan:32 33033
  PID WCHAN                            S TTY          TIME COMMAND
33033 nfs_wait_bit_uninterruptible     D ?        00:43:32 ...
# kill -9 33033
# ps -O wchan:32 33033
  PID WCHAN                            S TTY          TIME COMMAND
33033 nfs_wait_bit_uninterruptible     D ?        00:43:32 ...

My understanding is that processes in "uninterruptible sleep" are
not delivered signals until they resume from sleep, so they're immune
from `kill -9`.  

Thanks anyway!

Riccardo

-- 
Riccardo Murri, Anna-Heer-Strasse 10, CH-8057 ZÃ¼rich, Switzerland