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of: dynamic: Synchronize of_changeset_destroy() with the devlink removals

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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 <herve.codina@bootlin.com>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240325152140.198219-3-herve.codina@bootlin.com
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Herve Codina 2024-03-25 16:21:26 +01:00 committed by Ksawlii
parent d0b8ea4c92
commit 173a9fbfa8
1 changed files with 12 additions and 0 deletions
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12
drivers/of/dynamic.c
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@ -9,6 +9,7 @@
#define pr_fmt(fmt) "OF: " fmt
#include <linux/device.h>
#include <linux/of.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
@ -673,6 +674,17 @@ 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);
}