linux-kernel - [PATCH] pinctrl: pinmux: fix a possible null pointer in pinmux_can_be_used_for

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Date:   Wed, 4 Dec 2019 15:41:06 +0100
From:   Alexandre Torgue <alexandre.torgue@...com>
To:     Linus Walleij <linus.walleij@...aro.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <alexandre.torgue@...com>, Stefan Wahren <stefan.wahren@...e.com>
Subject: [PATCH] pinctrl: pinmux: fix a possible null pointer in pinmux_can_be_used_for_gpio

This commit adds a check on ops pointer to avoid a kernel panic when
ops->strict is used. Indeed, on some pinctrl driver (at least for
pinctrl-stmfx) the pinmux ops is not implemented. Let's assume than gpio
can be used in this case.

Fixes: 472a61e777fe ("pinctrl/gpio: Take MUX usage into account")

Signed-off-by: Alexandre Torgue <alexandre.torgue@...com>

diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index e914f6efd39e..9503ddf2edc7 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -85,7 +85,7 @@ bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned pin)
 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
 
 	/* Can't inspect pin, assume it can be used */
-	if (!desc)
+	if (!desc || !ops)
 		return true;
 
 	if (ops->strict && desc->mux_usecount)
-- 
2.17.1