Re: [PATCH v2 0/2] of: phandle_cache, fix refcounts, remove stale entry

On Mon, Dec 17, 2018 at 1:56 AM [off-list ref] wrote:

From: Frank Rowand <redacted>

Non-overlay dynamic devicetree node removal may leave the node in
the phandle cache.  Subsequent calls to of_find_node_by_phandle()
will incorrectly find the stale entry.  This bug exposed the foloowing
phandle cache refcount bug.

The refcount of phandle_cache entries is not incremented while in
the cache, allowing use after free error after kfree() of the
cached entry.

Changes since v1:
  - make __of_free_phandle_cache() static
  - add WARN_ON(1) for unexpected condition in of_find_node_by_phandle()

Frank Rowand (2):
  of: of_node_get()/of_node_put() nodes held in phandle cache
  of: __of_detach_node() - remove node from phandle cache

I'll send this to Linus this week if I get a tested by. Otherwise, it
will go in for 4.21.

Rob