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From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: saravanak@google.com,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	devicetree@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] of: property: Do not link to disabled devices
Date: Wed, 15 Apr 2020 17:05:47 +0200	[thread overview]
Message-ID: <20200415150550.28156-3-nsaenzjulienne@suse.de> (raw)
In-Reply-To: <20200415150550.28156-1-nsaenzjulienne@suse.de>

When creating a consumer/supplier relationship between two devices, make
sure the supplier node is actually active. Otherwise this will create a
device link that will never be fulfilled. This, in the worst case
scenario, will hang the system during boot.

Note that, in practice, the fact that a device-tree represented
consumer/supplier relationship isn't fulfilled will not prevent devices
from successfully probing.

Fixes: a3e1d1a7f5fc ("of: property: Add functional dependency link from DT bindings")
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 drivers/of/property.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index a8c2b13521b27..487685ff8bb19 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1052,6 +1052,13 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
 		return -ENODEV;
 	}
 
+	/* Don't allow linking a device node as consumer of a disabled node */
+	if (!of_device_is_available(sup_np)) {
+		dev_dbg(dev, "Not linking to %pOFP - Not available\n", sup_np);
+		of_node_put(sup_np);
+		return -ENODEV;
+	}
+
 	/*
 	 * Don't allow linking a device node as a consumer of one of its
 	 * descendant nodes. By definition, a child node can't be a functional
-- 
2.26.0


  parent reply	other threads:[~2020-04-15 15:06 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-15 15:05 [PATCH 0/4] of: property: fw_devlink misc fixes Nicolas Saenz Julienne
2020-04-15 15:05 ` [PATCH 1/4] of: property: Fix create device links for all child-supplier dependencies Nicolas Saenz Julienne
2020-04-15 18:20   ` Saravana Kannan
2020-04-15 18:22   ` Saravana Kannan
2020-04-16 11:32     ` Nicolas Saenz Julienne
2020-04-15 15:05 ` Nicolas Saenz Julienne [this message]
2020-04-15 18:30   ` [PATCH 2/4] of: property: Do not link to disabled devices Saravana Kannan
2020-04-16 11:37     ` Nicolas Saenz Julienne
2020-04-16 20:56       ` Saravana Kannan
2020-04-15 15:05 ` [PATCH 3/4] of: property: Move of_link_to_phandle() Nicolas Saenz Julienne
2020-04-15 15:05 ` [PATCH 4/4] of: property: Avoid linking devices with circular dependencies Nicolas Saenz Julienne
2020-04-15 18:52   ` Saravana Kannan
2020-04-16 16:01     ` Nicolas Saenz Julienne
2020-04-16 20:57       ` Saravana Kannan
2020-04-16 20:58       ` [PATCH v1] of: property: Don't retry device_link_add() upon failure Saravana Kannan
2020-04-17 16:50         ` Nicolas Saenz Julienne
2020-04-17 18:16         ` Rob Herring
2020-04-17 20:30           ` Saravana Kannan
2020-04-28 17:11         ` Rob Herring
2020-04-15 18:17 ` [PATCH 0/4] of: property: fw_devlink misc fixes Saravana Kannan
2020-04-16 11:02   ` Nicolas Saenz Julienne
2020-04-16 20:56     ` Saravana Kannan

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