[PATCH 1/2] staging: comedi: das16: deschedule timer routine on detach

Ian Abbott abbotti at mev.co.uk
Wed Oct 29 17:35:11 UTC 2014

The "das16" driver optionally uses a kernel timer and a DMA channel to
support asynchronous data acquisition, but currently never calls
`del_timer_sync()`.  There is some possibility the timer routine could
still be scheduled to run when the comedi "detach" handler is run to
clean up the device and cause a certain amount of havoc.  Avoid that by
calling `del_time_sync()` in the comedi "detach" handler
`das16_detach()` if the timer was initialized by the "attach" handler
`das16_attach()`.  Use the timer's `data` member to tell whether it was
initialized or not.

Signed-off-by: Ian Abbott <abbotti at mev.co.uk>
 drivers/staging/comedi/drivers/das16.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/staging/comedi/drivers/das16.c b/drivers/staging/comedi/drivers/das16.c
index 5d47d0a..51c4a58 100644
--- a/drivers/staging/comedi/drivers/das16.c
+++ b/drivers/staging/comedi/drivers/das16.c
@@ -1226,6 +1226,8 @@ static void das16_detach(struct comedi_device *dev)
 	int i;
 	if (devpriv) {
+		if (devpriv->timer.data)
+			del_timer_sync(&devpriv->timer);
 		if (dev->iobase)

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