From patchwork Sat Nov 11 15:31:18 2017
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Subject: USB: ulpi: fix bus-node lookup
From: Johan Hovold <johan@kernel.org>
X-Patchwork-Id: 10054387
Message-Id: <20171111153118.16038-1-johan@kernel.org>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-arm-msm@vger.kernel.org, Rob Clark <robdclark@gmail.com>,
 Peter Robinson <pbrobinson@gmail.com>, Johan Hovold <johan@kernel.org>,
 stable <stable@vger.kernel.org>
Date: Sat, 11 Nov 2017 16:31:18 +0100

Fix bus-node lookup during registration, which ended up searching the whole
device tree depth-first starting at the parent (or grand parent) rather
than just matching on its children.

To make things worse, the parent (or grand-parent) node could end being
prematurely freed as well.

Fixes: ef6a7bcfb01c ("usb: ulpi: Support device discovery via DT")
Reported-by: Peter Robinson <pbrobinson@gmail.com>
Reported-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: stable <stable@vger.kernel.org>     # 4.10
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/common/ulpi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
index 8b351444cc40..9a2ab6751a23 100644
--- a/drivers/usb/common/ulpi.c
+++ b/drivers/usb/common/ulpi.c
@@ -180,9 +180,9 @@ static int ulpi_of_register(struct ulpi *ulpi)
 	/* Find a ulpi bus underneath the parent or the grandparent */
 	parent = ulpi->dev.parent;
 	if (parent->of_node)
-		np = of_find_node_by_name(parent->of_node, "ulpi");
+		np = of_get_child_by_name(parent->of_node, "ulpi");
 	else if (parent->parent && parent->parent->of_node)
-		np = of_find_node_by_name(parent->parent->of_node, "ulpi");
+		np = of_get_child_by_name(parent->parent->of_node, "ulpi");
 	if (!np)
 		return 0;