diff options
author | Oleg Nesterov <oleg@redhat.com> | 2012-03-13 22:07:18 +0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-04-10 20:28:04 +0400 |
commit | ba46ce30f13a13bb24d05e21df2571ad724f1a1e (patch) | |
tree | 1bf3d9685389f6effee3db17307409abe9093e2d /drivers/staging/usbip | |
parent | 96ddcd439871658b797289dde8fcead8bde73b68 (diff) | |
download | linux-ba46ce30f13a13bb24d05e21df2571ad724f1a1e.tar.xz |
staging: usbip: fix the usage of kthread_stop()
stub_shutdown_connection() and vhci_shutdown_connection() use
task_is_dead() before kthread_stop(). This buys nothing and wrong.
kthread_stop() is fine even if this thread is dead. However, if it
is dead nothing protects this task_struct, we shouldn't touch this
memory.
Change the code to do the necessary get_task_struct/put_task_struct.
This patch assumes that
- xxx_shutdown_connection() is always called, so we can't
leak the task_struct.
- kthread_stop_put() can't be called twice on the same task.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Matt Mooney <mfm@muteddisk.com>,
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/usbip')
-rw-r--r-- | drivers/staging/usbip/stub_dev.c | 12 | ||||
-rw-r--r-- | drivers/staging/usbip/usbip_common.h | 17 | ||||
-rw-r--r-- | drivers/staging/usbip/vhci_hcd.c | 8 | ||||
-rw-r--r-- | drivers/staging/usbip/vhci_sysfs.c | 4 |
4 files changed, 29 insertions, 12 deletions
diff --git a/drivers/staging/usbip/stub_dev.c b/drivers/staging/usbip/stub_dev.c index fa870e3f7f6a..92ced35e6b7f 100644 --- a/drivers/staging/usbip/stub_dev.c +++ b/drivers/staging/usbip/stub_dev.c @@ -113,8 +113,8 @@ static ssize_t store_sockfd(struct device *dev, struct device_attribute *attr, spin_unlock(&sdev->ud.lock); - sdev->ud.tcp_rx = kthread_run(stub_rx_loop, &sdev->ud, "stub_rx"); - sdev->ud.tcp_tx = kthread_run(stub_tx_loop, &sdev->ud, "stub_tx"); + sdev->ud.tcp_rx = kthread_get_run(stub_rx_loop, &sdev->ud, "stub_rx"); + sdev->ud.tcp_tx = kthread_get_run(stub_tx_loop, &sdev->ud, "stub_tx"); spin_lock(&sdev->ud.lock); sdev->ud.status = SDEV_ST_USED; @@ -187,10 +187,10 @@ static void stub_shutdown_connection(struct usbip_device *ud) } /* 1. stop threads */ - if (ud->tcp_rx && !task_is_dead(ud->tcp_rx)) - kthread_stop(ud->tcp_rx); - if (ud->tcp_tx && !task_is_dead(ud->tcp_tx)) - kthread_stop(ud->tcp_tx); + if (ud->tcp_rx) + kthread_stop_put(ud->tcp_rx); + if (ud->tcp_tx) + kthread_stop_put(ud->tcp_tx); /* * 2. close the socket diff --git a/drivers/staging/usbip/usbip_common.h b/drivers/staging/usbip/usbip_common.h index c7b888ca54f5..5d89c0fd6f7b 100644 --- a/drivers/staging/usbip/usbip_common.h +++ b/drivers/staging/usbip/usbip_common.h @@ -292,6 +292,23 @@ struct usbip_device { } eh_ops; }; +#define kthread_get_run(threadfn, data, namefmt, ...) \ +({ \ + struct task_struct *__k \ + = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \ + if (!IS_ERR(__k)) { \ + get_task_struct(__k); \ + wake_up_process(__k); \ + } \ + __k; \ +}) + +#define kthread_stop_put(k) \ + do { \ + kthread_stop(k); \ + put_task_struct(k); \ + } while (0) + /* usbip_common.c */ void usbip_dump_urb(struct urb *purb); void usbip_dump_header(struct usbip_header *pdu); diff --git a/drivers/staging/usbip/vhci_hcd.c b/drivers/staging/usbip/vhci_hcd.c index dca9bf11f0c2..f708cbaee16b 100644 --- a/drivers/staging/usbip/vhci_hcd.c +++ b/drivers/staging/usbip/vhci_hcd.c @@ -821,10 +821,10 @@ static void vhci_shutdown_connection(struct usbip_device *ud) } /* kill threads related to this sdev, if v.c. exists */ - if (vdev->ud.tcp_rx && !task_is_dead(vdev->ud.tcp_rx)) - kthread_stop(vdev->ud.tcp_rx); - if (vdev->ud.tcp_tx && !task_is_dead(vdev->ud.tcp_tx)) - kthread_stop(vdev->ud.tcp_tx); + if (vdev->ud.tcp_rx) + kthread_stop_put(vdev->ud.tcp_rx); + if (vdev->ud.tcp_tx) + kthread_stop_put(vdev->ud.tcp_tx); pr_info("stop threads\n"); diff --git a/drivers/staging/usbip/vhci_sysfs.c b/drivers/staging/usbip/vhci_sysfs.c index 0cd039bb5fd6..7ce9c2f7e442 100644 --- a/drivers/staging/usbip/vhci_sysfs.c +++ b/drivers/staging/usbip/vhci_sysfs.c @@ -222,8 +222,8 @@ static ssize_t store_attach(struct device *dev, struct device_attribute *attr, spin_unlock(&the_controller->lock); /* end the lock */ - vdev->ud.tcp_rx = kthread_run(vhci_rx_loop, &vdev->ud, "vhci_rx"); - vdev->ud.tcp_tx = kthread_run(vhci_tx_loop, &vdev->ud, "vhci_tx"); + vdev->ud.tcp_rx = kthread_get_run(vhci_rx_loop, &vdev->ud, "vhci_rx"); + vdev->ud.tcp_tx = kthread_get_run(vhci_tx_loop, &vdev->ud, "vhci_tx"); rh_port_connect(rhport, speed); |