tree df07d83f518cbcc1fd7b54bcd0d16402dbc2db1d
parent c88f9906c36de61a59a99e109ff04d5b0a4a29d1
author Tobias Klauser <tklauser@distanz.ch> 1308923327 +0200
committer Greg Kroah-Hartman <gregkh@suse.de> 1309922050 -0700

Staging: usbip: vhci-hcd: Do not kill already dead RX/TX kthread

When unbinding a device on the host which was still attached on the
client, I got a NULL pointer dereference on the client. This turned out
to be due to kthread_stop() being called on an already dead kthread.

Here is how I was able to reproduce the problem:

 server:# usbip bind -b 1-2
                                client:# usbip attach -h server -b 1-2
 server:# usbip unbind -b 1-2

This patch fixes the problem by checking the kthread before attempting
to kill it, as it is done on the opposite side in
stub_shutdown_connection().

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>