From: Tobias Klauser <tklauser@distanz.ch>
Date: Fri, 24 Jun 2011 13:48:47 +0000 (+0200)
Subject: Staging: usbip: vhci-hcd: Do not kill already dead RX/TX kthread
X-Git-Tag: v3.1-rc1~232^2~97
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8547d4cc2b616e4f1dafebe2c673fc986422b506;p=pandora-kernel.git

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>
---

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