Re: [PATCH v03] powerpc/mobility: Fix node detach/rename problem

Rob Herring [off-list ref] writes:

On Tue, Dec 11, 2018 at 7:29 AM Michael Ellerman [off-list ref] wrote:

...

quoted

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 09692c9b32a7..d8e4534c0686 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c

@@ -1190,6 +1190,10 @@ struct device_node *of_find_node_by_phandle(phandle handle)
                if (phandle_cache[masked_handle] &&
                    handle == phandle_cache[masked_handle]->phandle)
                        np = phandle_cache[masked_handle];
+
+               /* If we find a detached node, remove it */
+               if (of_node_check_flag(np, OF_DETACHED))
+                       np = phandle_cache[masked_handle] = NULL;

I'm wondering if we should explicitly remove the node from the cache
when we set OF_DETACHED. Otherwise, it could be possible that the node
pointer has been freed already.

Yeah good point.

Or maybe we need both?

That's probably best, it could even be a WARN_ON() if we find one in
of_find_node_by_phandle().

cheers