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>
---
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;
}
/*
--
2.39.2
