On Thu May 1 11:44:44 2025 +0200, Hans de Goede wrote:
> When a (sensor) v4l2_subdev has its state_lock member set to non NULL,
> then all v4l2_subdev_state-s for the sensor share the same lock.
>
> atomisp_init_sensor() calls v4l2_subdev_lock_and_get_active_state() and
> then later on also tries to lock a separate v4l2_subdev_state used for try
> calls (rather then changing the active state), while still holding
> the active state lock.
>
> Since this try v4l2_subdev_state shares a lock with the active state this
> results in a deadlock.
>
> Skip locking try_sd_state when sensor->state_lock is set to avoid this.
>
> Signed-off-by: Hans de Goede <hdego...@redhat.com>
> Reviewed-by: Andy Shevchenko <a...@kernel.org>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>
Patch committed.
Thanks,
Mauro Carvalho Chehab
drivers/staging/media/atomisp/pci/atomisp_v4l2.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
index 03c535bcb229..ac8fefca7922 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
@@ -963,10 +963,17 @@ static void atomisp_init_sensor(struct
atomisp_input_subdev *input)
sel.which = V4L2_SUBDEV_FORMAT_TRY;
sel.target = V4L2_SEL_TGT_CROP;
sel.r = input->native_rect;
- v4l2_subdev_lock_state(input->try_sd_state);
+
+ /* Don't lock try_sd_state if the lock is shared with the active state
*/
+ if (!input->sensor->state_lock)
+ v4l2_subdev_lock_state(input->try_sd_state);
+
err = v4l2_subdev_call(input->sensor, pad, set_selection,
input->try_sd_state, &sel);
- v4l2_subdev_unlock_state(input->try_sd_state);
+
+ if (!input->sensor->state_lock)
+ v4l2_subdev_unlock_state(input->try_sd_state);
+
if (err)
goto unlock_act_sd_state;
