5.4-stable review patch. If anyone has any objections, please let me know.
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From: Ian Abbott abbotti@mev.co.uk
commit 1b98304c09a0192598d0767f1eb8c83d7e793091 upstream.
In `waveform_common_attach()`, the two timers `&devpriv->ai_timer` and `&devpriv->ao_timer` are initialized after the allocation of the device private data by `comedi_alloc_devpriv()` and the subdevices by `comedi_alloc_subdevices()`. The function may return with an error between those function calls. In that case, `waveform_detach()` will be called by the Comedi core to clean up. The check that `waveform_detach()` uses to decide whether to delete the timers is incorrect. It only checks that the device private data was allocated, but that does not guarantee that the timers were initialized. It also needs to check that the subdevices were allocated. Fix it.
Fixes: 73e0e4dfed4c ("staging: comedi: comedi_test: fix timer lock-up") Cc: stable@vger.kernel.org # 6.15+ Signed-off-by: Ian Abbott abbotti@mev.co.uk Link: https://lore.kernel.org/r/20250708130627.21743-1-abbotti@mev.co.uk [ file location from drivers/comedi to drivers/staging/comedi and timer_delete_sync() to del_timer_sync(). ] Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/staging/comedi/drivers/comedi_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/staging/comedi/drivers/comedi_test.c +++ b/drivers/staging/comedi/drivers/comedi_test.c @@ -790,7 +790,7 @@ static void waveform_detach(struct comed { struct waveform_private *devpriv = dev->private;
- if (devpriv) { + if (devpriv && dev->n_subdevices) { del_timer_sync(&devpriv->ai_timer); del_timer_sync(&devpriv->ao_timer); }