2024-06-13 15:02:15

by Gyeonggeon Choi

Subject: [PATCH] drivers:of: Add null check for bus in of_match_bus

Added a null check for the bus variable after calling of_match_bus.
This prevents potential null pointer dereference errors in subsequent
code, where bus->count_cells could cause a crash if bus is NULL.

Signed-off-by: Gyeonggeon Choi <[email protected]>
---
drivers/of/address.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index d669ce25b5f9..85f986d25870 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -504,6 +504,8 @@ static u64 __of_translate_address(struct device_node *node,
if (parent == NULL)
return OF_BAD_ADDR;
bus = of_match_bus(parent);
+ if (bus == NULL)
+ return OF_BAD_ADDR;

/* Count address cells & copy address locally */
bus->count_cells(dev, &na, &ns);
--
2.39.3 (Apple Git-146)

2024-06-13 15:53:38

by Rob Herring (Arm)

Subject: Re: [PATCH] drivers:of: Add null check for bus in of_match_bus

On Thu, Jun 13, 2024 at 9:02 AM Gyeonggeon Choi <[email protected]> wrote:
>
> Added a null check for the bus variable after calling of_match_bus.
> This prevents potential null pointer dereference errors in subsequent
> code, where bus->count_cells could cause a crash if bus is NULL.

Go read of_match_bus(). It never returns NULL and if somehow it did,
we'll BUG() first.

>
> Signed-off-by: Gyeonggeon Choi <[email protected]>
> ---
> drivers/of/address.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index d669ce25b5f9..85f986d25870 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -504,6 +504,8 @@ static u64 __of_translate_address(struct device_node *node,
> if (parent == NULL)
> return OF_BAD_ADDR;
> bus = of_match_bus(parent);
> + if (bus == NULL)
> + return OF_BAD_ADDR;
>
> /* Count address cells & copy address locally */
> bus->count_cells(dev, &na, &ns);
> --
> 2.39.3 (Apple Git-146)
>