Hi All, I did a mistake in this series. As noted by Nuno, the device.h include is missing in patch 2 and so the patch 2 doesn't compile :( A v3 is already sent fixing my missing device.h mistake. https://lore.kernel.org/all/20240229105204.720717-1-herve.codina@xxxxxxxxxxx/ Sorry for this error. Best regards, Hervé On Thu, 29 Feb 2024 09:39:40 +0100 Herve Codina <herve.codina@xxxxxxxxxxx> 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/20231130174126.688486-1-herve.codina@xxxxxxxxxxx/ > this v2 series mainly: > - Renames the workqueue used. > - Calls device_link_wait_removal() a bit later to handle 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 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: overlay: Synchronize of_overlay_remove() with the devlink removals > > drivers/base/core.c | 26 +++++++++++++++++++++++--- > drivers/of/overlay.c | 9 ++++++++- > include/linux/device.h | 1 + > 3 files changed, 32 insertions(+), 4 deletions(-) >
