On Fri, Mar 08, 2024 at 02:29:28PM -0800, Saravana Kannan wrote: > On Fri, Mar 8, 2024 at 12:05 PM Rob Herring <robh@xxxxxxxxxx> wrote: > > > > 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. > > Reviewed-by: Saravana Kannan <saravanak@xxxxxxxxxx> Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
