On Thu, Nov 30, 2023 at 9:41 AM Herve Codina <herve.codina@xxxxxxxxxxx> wrote: > > In the following sequence: > 1) of_platform_depopulate() > 2) of_overlay_remove() > > During the step 1, devices are destroyed and devlinks are removed. > During the step 2, OF nodes are destroyed but > __of_changeset_entry_destroy() can raise warnings related to missing > of_node_put(): > ERROR: memory leak, expected refcount 1 instead of 2 ... > > Indeed, during the devlink removals performed at step 1, the removal > itself releasing the device (and the attached of_node) is done by a job > queued in a workqueue and so, it is done asynchronously with respect to > function calls. > When the warning is present, of_node_put() will be called but wrongly > too late from the workqueue job. > > In order to be sure that any ongoing devlink removals are done before > the of_node destruction, synchronize the of_overlay_remove() with the > devlink removals. > Add Fixes tag for this one too to point to the change that added the workqueue. Please CC Nuno and Luca in your v2 series. > Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx> > --- > drivers/of/overlay.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c > index a9a292d6d59b..5c5f808b163e 100644 > --- a/drivers/of/overlay.c > +++ b/drivers/of/overlay.c > @@ -1202,6 +1202,12 @@ int of_overlay_remove(int *ovcs_id) > goto out; > } > > + /* > + * Wait for any ongoing device link removals before removing some of > + * nodes > + */ > + device_link_wait_removal(); > + Nuno in his patch[1] had this "wait" happen inside __of_changeset_entry_destroy(). Which seems to be necessary to not hit the issue that Luca reported[2] in this patch series. Is there any problem with doing that? Luca for some reason did a unlock/lock(of_mutex) in his test patch and I don't think that's necessary. Can you move this call to where Nuno did it and see if that works for all of you? [1] - https://lore.kernel.org/all/20240205-fix-device-links-overlays-v2-2-5344f8c79d57@xxxxxxxxxx/ [2] - https://lore.kernel.org/all/20231220181627.341e8789@booty/ Thank, Saravana > mutex_lock(&of_mutex); > > ovcs = idr_find(&ovcs_idr, *ovcs_id); > -- > 2.42.0 > >
