linux-kernel - [PATCH 4/7] driver core: fix automatic pinctrl management

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20170530162554.26159-5-johan@kernel.org>
Date:   Tue, 30 May 2017 18:25:51 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Peter Chen <peter.chen@...escale.com>,
        Rob Herring <robh@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        Sricharan R <sricharan@...eaurora.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Eduardo Valentin <edubezval@...il.com>,
        linux-pm@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, Johan Hovold <johan@...nel.org>
Subject: [PATCH 4/7] driver core: fix automatic pinctrl management

Commit ab78029ecc34 ("drivers/pinctrl: grab default handles from device
core") added automatic pin-control management to driver core by looking
up and setting any default pinctrl state found in device tree while a
device is being probed.

This obviously runs into problems as soon as device-tree nodes are
reused for child devices which are later also probed as pins would
already have been claimed by the ancestor device.

For example if a USB host controller claims a pin, its root hub would
consequently fail to probe when its device-tree node is set to the node
of the controller:

    pinctrl-single 48002030.pinmux: pin PIN204 already requested by 48064800.ehci; cannot claim for usb1
    pinctrl-single 48002030.pinmux: pin-204 (usb1) status -22
    pinctrl-single 48002030.pinmux: could not request pin 204 (PIN204) from group usb_dbg_pins  on device pinctrl-single
    usb usb1: Error applying setting, reverse things back
    usb: probe of usb1 failed with error -22

Fix this by checking the new of_node_reused flag and skipping automatic
pinctrl configuration during probe if set.

Note that the flag is checked in driver core rather than in pinctrl
(e.g. in pinctrl_dt_to_map()) which would specifically have prevented
intentional use of a parent's pinctrl properties by a child device
(should such a need ever arise).

Fixes: ab78029ecc34 ("drivers/pinctrl: grab default handles from device core")
Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/base/pinctrl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/base/pinctrl.c b/drivers/base/pinctrl.c
index 5917b4b5fb99..eb929dd6ef1e 100644
--- a/drivers/base/pinctrl.c
+++ b/drivers/base/pinctrl.c
@@ -23,6 +23,9 @@ int pinctrl_bind_pins(struct device *dev)
 {
 	int ret;
 
+	if (dev->of_node_reused)
+		return 0;
+
 	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
 	if (!dev->pins)
 		return -ENOMEM;
-- 
2.13.0