Re: [PATCH v2 2/2] of: __of_detach_node() - remove node from phandle cache

On 12/18/18 12:01 PM, Rob Herring wrote:

On Tue, Dec 18, 2018 at 12:57 PM Frank Rowand [off-list ref] wrote:

quoted

On 12/17/18 2:52 AM, Michael Ellerman wrote:

quoted

Hi Frank,

frowand.list@gmail.com writes:

quoted

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.  Remove the node from the
cache.

Add paranoia checks in of_find_node_by_phandle() as a second level
of defense (do not return cached node if detached, do not add node
to cache if detached).

Reported-by: Michael Bringmann <redacted>
Signed-off-by: Frank Rowand <redacted>
---

Similarly here can we add:

Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()")

Yes, thanks.

quoted

Cc: stable@vger.kernel.org # v4.17+

Nope, 0b3ce78e90fc does not belong in stable (it is a feature, not a bug
fix).  So the bug will not be in stable.

0b3ce78e90fc landed in v4.17, so Michael's line above is correct.
Annotating it with 4.17 only saves Greg from trying and then emailing
us to backport this patch as it wouldn't apply.

Thanks for the correction.  I was both under-thinking and over-thinking,
ending up with an incorrect answer.

Can you add the Cc: to version 3 patch comments (both 1/2 and 2/2) or do
you want me to re-spin?

-Frank

Rob