From 801c8b8ec5bfb3519566dff16a5ecd48302fca82 Mon Sep 17 00:00:00 2001 From: Herve Codina Date: Mon, 25 Mar 2024 16:21:26 +0100 Subject: [PATCH] of: dynamic: Synchronize of_changeset_destroy() with the devlink removals commit 8917e7385346bd6584890ed362985c219fe6ae84 upstream. 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_changeset_destroy() with the devlink removals. Fixes: 80dd33cf72d1 ("drivers: base: Fix device link removal") Cc: stable@vger.kernel.org Signed-off-by: Herve Codina Reviewed-by: Saravana Kannan Tested-by: Luca Ceresoli Reviewed-by: Nuno Sa Link: https://lore.kernel.org/r/20240325152140.198219-3-herve.codina@bootlin.com Signed-off-by: Rob Herring Signed-off-by: Greg Kroah-Hartman --- drivers/of/dynamic.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c index 3bf27052832f3..4d57a4e341054 100644 --- a/drivers/of/dynamic.c +++ b/drivers/of/dynamic.c @@ -9,6 +9,7 @@ #define pr_fmt(fmt) "OF: " fmt +#include #include #include #include @@ -667,6 +668,17 @@ void of_changeset_destroy(struct of_changeset *ocs) { struct of_changeset_entry *ce, *cen; + /* + * When a device is deleted, the device links to/from it are also queued + * for deletion. Until these device links are freed, the devices + * themselves aren't freed. If the device being deleted is due to an + * overlay change, this device might be holding a reference to a device + * node that will be freed. So, wait until all already pending device + * links are deleted before freeing a device node. This ensures we don't + * free any device node that has a non-zero reference count. + */ + device_link_wait_removal(); + list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node) __of_changeset_entry_destroy(ce); }