[PATCH] clk: handle get_parent callbacks returning an error

[PATCH] clk: handle get_parent callbacks returning an error

[Ahmad Fatoum]

A mux with a value table returns -EINVAL from get_parent when the
register holds a value missing from the table. clk_get_parent() only
rejected indices >= num_parents, so -EINVAL went on to index the
parents array as u8 234 and clk_dump crashed on the Amlogic G12 clock
controller.

Let's return -ENODEV for negative indices as well.

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 drivers/clk/clk.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 99f995fb0224..1d6aaa46d9b1 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -382,7 +382,8 @@ struct clk *clk_get_parent(struct clk *clk)
 
 		idx = clk->ops->get_parent(hw);
 
-		if (idx >= clk->num_parents)
+		/* an error means the register selects no known parent */
+		if (idx < 0 || idx >= clk->num_parents)
 			return ERR_PTR(-ENODEV);
 	} else {
 		idx = 0;
-- 
2.47.3

Re: [PATCH] clk: handle get_parent callbacks returning an error

[Sascha Hauer]

On Sun, 25 Oct 2026 10:31:20 +0100, Ahmad Fatoum wrote:
> A mux with a value table returns -EINVAL from get_parent when the
> register holds a value missing from the table. clk_get_parent() only
> rejected indices >= num_parents, so -EINVAL went on to index the
> parents array as u8 234 and clk_dump crashed on the Amlogic G12 clock
> controller.
> 
> Let's return -ENODEV for negative indices as well.
> 
> [...]

Applied, thanks!

[1/1] clk: handle get_parent callbacks returning an error
      https://git.pengutronix.de/cgit/barebox/commit/?id=22f58f5dea50 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>