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authorSebastian Ott <sebott@linux.vnet.ibm.com>2009-09-11 10:28:20 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2009-09-11 10:29:38 +0200
commitbe7a2ddce66991c05a1c6ad19790289591e53547 (patch)
tree89b74961a7da107e7eebe4486f48bb9c4426938e /drivers/s390
parente2910bcf8ca762b306767a0894ab1987be014c9e (diff)
[S390] cio: ensure to hold a reference for deferred deregistration
Ensure to always hold an extra device reference for scheduling a subchannel deregistration, by moving the get_device to ccw_device_schedule_sch_unregister. This fixes an use after free error in ccw_device_call_sch_unregister where put_device was called on an already freed device structure. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390')
-rw-r--r--drivers/s390/cio/device.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 19b4469a3ca..a7a340b1d71 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -333,15 +333,15 @@ ccw_device_remove_disconnected(struct ccw_device *cdev)
* Forced offline in disconnected state means
* 'throw away device'.
*/
- /* Get cdev reference for workqueue processing. */
- if (!get_device(&cdev->dev))
- return;
if (ccw_device_is_orphan(cdev)) {
/*
* Deregister ccw device.
* Unfortunately, we cannot do this directly from the
* attribute method.
*/
+ /* Get cdev reference for workqueue processing. */
+ if (!get_device(&cdev->dev))
+ return;
spin_lock_irqsave(cdev->ccwlock, flags);
cdev->private->state = DEV_STATE_NOT_OPER;
spin_unlock_irqrestore(cdev->ccwlock, flags);
@@ -1032,6 +1032,9 @@ static void ccw_device_call_sch_unregister(struct work_struct *work)
void ccw_device_schedule_sch_unregister(struct ccw_device *cdev)
{
+ /* Get cdev reference for workqueue processing. */
+ if (!get_device(&cdev->dev))
+ return;
PREPARE_WORK(&cdev->private->kick_work,
ccw_device_call_sch_unregister);
queue_work(slow_path_wq, &cdev->private->kick_work);
@@ -1052,9 +1055,6 @@ io_subchannel_recog_done(struct ccw_device *cdev)
/* Device did not respond in time. */
case DEV_STATE_NOT_OPER:
cdev->private->flags.recog_done = 1;
- /* Remove device found not operational. */
- if (!get_device(&cdev->dev))
- break;
ccw_device_schedule_sch_unregister(cdev);
if (atomic_dec_and_test(&ccw_device_init_count))
wake_up(&ccw_device_init_wq);
@@ -1565,8 +1565,6 @@ static int purge_fn(struct device *dev, void *data)
spin_unlock_irq(cdev->ccwlock);
if (!unreg)
goto out;
- if (!get_device(&cdev->dev))
- goto out;
CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", priv->dev_id.ssid,
priv->dev_id.devno);
ccw_device_schedule_sch_unregister(cdev);