On 07.06.23 10:08, Ahmad Fatoum wrote:
> of_get_devicepath code flow is split into two:
>
> A) Either the device tree node in question has a direct udev_device
> associated with it
>
> B) Or we assume it's a partition and lookup udev_device for the parent
> first, before finding a child udev_device or setting a partition
> offset within the parent udev_device.
>
> Since v2017.03.0, we have had a fallthrough from case A into case B:
> If we have a udev_device, but it's neither a EEPROMs, MTDs or block
> device, we just consider it a partition. This is problematic, because
> this may result in us pointing at a very different device:
>
> - backend points at a SD-Card host. Host is enabled, but SD-Card
> is not inserted, so no block device
>
> - case A fails, so it's assumed it's a partition and case B
> uses parent SoC bus to lookup appropriate device
>
> - We fall through into the second device_find_block_device, which
> will take the first matching block device across the SoC. So
> we could end up with the eMMC: a completely different device
> than what was pointed at.
>
> Fixes: 929ed64cb42f ("of_get_devicepath: make partition finding more robust")
> Signed-off-by: Ahmad Fatoum <a.fat...@pengutronix.de>
Patch applied to next.
> ---
> src/libdt.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/src/libdt.c b/src/libdt.c
> index e54d7fb5649d..7b99efe5b2de 100644
> --- a/src/libdt.c
> +++ b/src/libdt.c
> @@ -2492,9 +2492,11 @@ int of_get_devicepath(struct device_node
> *partition_node, char **devpath, off_t
> }
>
> /*
> - * If we found a device but couldn't classify it above, we fall
> - * through.
> + * If we find a udev_device but couldn't classify it above,
> + * it's an error. Falling through would mean to handle it as a
> + * partition and could lead us to return an arbitrary sibling
> device
> */
> + return -ENODEV;
> }
>
> /*
--
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