Hi Rob,
On Tue, Aug 22, 2023 at 1:33 AM Rob Herring <robh@xxxxxxxxxx> wrote:
> On Mon, 21 Aug 2023 10:39:28 +0800, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan@xxxxxxx>
> >
> > commit 0f8e5651095b
> > ("of/platform: Propagate firmware node by calling device_set_node()")
> > use of_fwnode_handle to replace of_node_get, which introduces a side
> > effect that the refcount is not increased. Then the out of tree
> > jailhouse hypervisor enable/disable test will trigger kernel dump in
> > of_overlay_remove, with the following sequence
> > "
> > of_changeset_revert(&overlay_changeset);
> > of_changeset_destroy(&overlay_changeset);
> > of_overlay_remove(&overlay_id);
> > "
> >
> > So increase the refcount to avoid issues.
> >
> > This patch also release the refcount when releasing amba device to avoid
> > refcount leakage.
> >
> > Fixes: 0f8e5651095b ("of/platform: Propagate firmware node by calling device_set_node()")
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> > ---
> >
> > V3:
> > - Move amba device changes to patch 1/1
> >
> > V2:
> > - Per Andy's comment, use of_fwnode_handle(of_node_get(np))
> > - release amba device of_node refcount when releasing amba device, this is
> > done from code inspection, no test.
> >
> > drivers/of/platform.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
>
> Applied, thanks!
Good to see this got applied!
I had missed this fix, and spent quite some time investigating why multiple
overlay add/removal sequences caused a crash. Only after I had
written a reproducer unittest[1], I managed to bisect the issue,
and found Peng's fix. Thanks!
Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
[1] "[PATCH] of: unittest: Run overlay apply/revert sequence three times"
https://lore.kernel.org/all/a9fb4eb560c58d11a7f167bc78a137b46e76cf15.1692699743.git.geert+renesas@xxxxxxxxx/
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
