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| author | Sebastian Ott <sebott@linux.vnet.ibm.com> | 2009-09-11 10:28:20 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2009-09-11 10:29:38 +0200 |
| commit | be7a2ddce66991c05a1c6ad19790289591e53547 (patch) | |
| tree | 89b74961a7da107e7eebe4486f48bb9c4426938e | |
| parent | e2910bcf8ca762b306767a0894ab1987be014c9e (diff) | |
| download | linux-be7a2ddce66991c05a1c6ad19790289591e53547.tar.bz2 | |
[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>
| -rw-r--r-- | drivers/s390/cio/device.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index 19b4469a3ca4..a7a340b1d713 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); |