On Thu, Mar 07, 2024 at 12:09:59PM +0100, Herve Codina wrote: > Hi, > > In the following sequence: > of_platform_depopulate(); /* Remove devices from a DT overlay node */ > of_overlay_remove(); /* Remove the DT overlay node itself */ > > Some warnings are raised by __of_changeset_entry_destroy() which was > called from of_overlay_remove(): > ERROR: memory leak, expected refcount 1 instead of 2 ... > > The issue is that, during the device devlink removals triggered from the > of_platform_depopulate(), jobs are put in a workqueue. > These jobs drop the reference to the devices. When a device is no more > referenced (refcount == 0), it is released and the reference to its > of_node is dropped by a call to of_node_put(). > These operations are fully correct except that, because of the > workqueue, they are done asynchronously with respect to function calls. > > In the sequence provided, the jobs are run too late, after the call to > __of_changeset_entry_destroy() and so a missing of_node_put() call is > detected by __of_changeset_entry_destroy(). > > This series fixes this issue introducing device_link_wait_removal() in > order to wait for the end of jobs execution (patch 1) and using this > function to synchronize the overlay removal with the end of jobs > execution (patch 2). > > Compared to the previous iteration: > https://lore.kernel.org/linux-kernel/20240306085007.169771-1-herve.codina@xxxxxxxxxxx/ > this v5 series: > - Remove a 'Fixes' tag > - Update a comment > - Add 'Tested-by' and ''Reviewed-by' tags > > This series handles cases reported by Luca [1] and Nuno [2]. > [1]: https://lore.kernel.org/all/20231220181627.341e8789@booty/ > [2]: https://lore.kernel.org/all/20240205-fix-device-links-overlays-v2-2-5344f8c79d57@xxxxxxxxxx/ > > Best regards, > Hervé > > Changes v4 -> v5 > - Patch 1 > Remove the 'Fixes' tag > Add 'Tested-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>' > Add 'Reviewed-by: Nuno Sa <nuno.sa@xxxxxxxxxx>' > > - Patch 2 > Update comment as suggested > Add 'Reviewed-by: Saravana Kannan <saravanak@xxxxxxxxxx>' > Add 'Tested-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>' > Add 'Reviewed-by: Nuno Sa <nuno.sa@xxxxxxxxxx>' > > Changes v3 -> v4 > - Patch 1 > Uses flush_workqueue() instead of drain_workqueue(). > > - Patch 2 > Remove unlock/re-lock when calling device_link_wait_removal() > Move device_link_wait_removal() call to of_changeset_destroy() > Update commit log > > Changes v2 -> v3 > - Patch 1 > No changes > > - Patch 2 > Add missing device.h > > Changes v1 -> v2 > - Patch 1 > Rename the workqueue to 'device_link_wq' > Add 'Fixes' tag and Cc stable > > - Patch 2 > Add device.h inclusion. > Call device_link_wait_removal() later in the overlay removal > sequence (i.e. in free_overlay_changeset() function). > Drop of_mutex lock while calling device_link_wait_removal(). > Add 'Fixes' tag and Cc stable > > Herve Codina (2): > driver core: Introduce device_link_wait_removal() > of: dynamic: Synchronize of_changeset_destroy() with the devlink > removals > > drivers/base/core.c | 26 +++++++++++++++++++++++--- > drivers/of/dynamic.c | 12 ++++++++++++ > include/linux/device.h | 1 + > 3 files changed, 36 insertions(+), 3 deletions(-) This looks good to me. I can take this given the user is DT. Looking for a R-by from Saravana and Ack from Greg. A R-by from Rafael would be great too. Rob
