Subject: CVE-2024-35879: of: dynamic: Synchronize of_changeset_destroy() with the devlink removals

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

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

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.

The Linux kernel CVE team has assigned CVE-2024-35879 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.10.42 with commit d007150b4e15 and fixed in 5.10.215 with commit 3127b2ee50c4
	Issue introduced in 5.13 with commit 80dd33cf72d1 and fixed in 5.15.154 with commit 3ee242410754
	Issue introduced in 5.13 with commit 80dd33cf72d1 and fixed in 6.1.85 with commit 7b6df050c45a
	Issue introduced in 5.13 with commit 80dd33cf72d1 and fixed in 6.6.26 with commit 801c8b8ec5bf
	Issue introduced in 5.13 with commit 80dd33cf72d1 and fixed in 6.8.5 with commit ae6d76e4f06c
	Issue introduced in 5.13 with commit 80dd33cf72d1 and fixed in 6.9 with commit 8917e7385346
	Issue introduced in 5.12.9 with commit 252c23915546

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-35879
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/of/dynamic.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/3127b2ee50c424a96eb3559fbb7b43cf0b111c7a
	https://git.kernel.org/stable/c/3ee2424107546d882e1ddd75333ca9c32879908c
	https://git.kernel.org/stable/c/7b6df050c45a1ea158fd50bc32a8e1447dd1e951
	https://git.kernel.org/stable/c/801c8b8ec5bfb3519566dff16a5ecd48302fca82
	https://git.kernel.org/stable/c/ae6d76e4f06c37a623e357e79d49b17411db6f5c
	https://git.kernel.org/stable/c/8917e7385346bd6584890ed362985c219fe6ae84