From: Ian Abbott Date: Tue, 8 Jul 2025 13:06:27 +0000 (+0100) Subject: comedi: comedi_test: Fix possible deletion of uninitialized timers X-Git-Tag: v6.16-rc7~10^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1b98304c09a0192598d0767f1eb8c83d7e793091;p=thirdparty%2Flinux.git comedi: comedi_test: Fix possible deletion of uninitialized timers 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 Link: https://lore.kernel.org/r/20250708130627.21743-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/comedi/drivers/comedi_test.c b/drivers/comedi/drivers/comedi_test.c index 9747e6d1f6eb8..7984950f0f992 100644 --- a/drivers/comedi/drivers/comedi_test.c +++ b/drivers/comedi/drivers/comedi_test.c @@ -792,7 +792,7 @@ static void waveform_detach(struct comedi_device *dev) { struct waveform_private *devpriv = dev->private; - if (devpriv) { + if (devpriv && dev->n_subdevices) { timer_delete_sync(&devpriv->ai_timer); timer_delete_sync(&devpriv->ao_timer); }