From 4a7822e8d3d2e9af6cd22e208a928974a78fee04 Mon Sep 17 00:00:00 2001 From: Tobias Klauser Date: Fri, 24 Jun 2011 15:48:47 +0200 Subject: Staging: usbip: vhci-hcd: Do not kill already dead RX/TX kthread commit 8547d4cc2b616e4f1dafebe2c673fc986422b506 upstream. 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 Signed-off-by: Greg Kroah-Hartman Change-Id: I9aaa60ee923506237a325afdaf908a5dbd7be60e Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/35585 Tested-by: Per VAHLNE Reviewed-by: Jonas ABERG --- drivers/staging/usbip/vhci_hcd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/staging/usbip/vhci_hcd.c b/drivers/staging/usbip/vhci_hcd.c index a76e8fa69b6..76d7485f4e2 100644 --- a/drivers/staging/usbip/vhci_hcd.c +++ b/drivers/staging/usbip/vhci_hcd.c @@ -846,9 +846,9 @@ static void vhci_shutdown_connection(struct usbip_device *ud) } /* kill threads related to this sdev, if v.c. exists */ - if (vdev->ud.tcp_rx) + if (vdev->ud.tcp_rx && !task_is_dead(vdev->ud.tcp_rx)) kthread_stop(vdev->ud.tcp_rx); - if (vdev->ud.tcp_tx) + if (vdev->ud.tcp_tx && !task_is_dead(vdev->ud.tcp_tx)) kthread_stop(vdev->ud.tcp_tx); pr_info("stop threads\n"); -- cgit v1.2.3