From: Richard Genoud <richard.genoud@gmail.com>
Date: Thu, 21 Mar 2013 11:21:47 +0000 (+0100)
Subject: pinmux: forbid mux_usecount to be set at UINT_MAX
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=740924a267e85de09707ea158bbf594b4d8bae01;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

pinmux: forbid mux_usecount to be set at UINT_MAX

If pin_free is called on a pin already freed, mux_usecount is set to
UINT_MAX which is really a bad idea.

This will issue a warning, so that we can correct the code responsible
for the double free.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---

diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index 1a00658b3ea0..bd83c8b01cd1 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -194,6 +194,11 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 	}
 
 	if (!gpio_range) {
+		/*
+		 * A pin should not be freed more times than allocated.
+		 */
+		if (WARN_ON(!desc->mux_usecount))
+			return NULL;
 		desc->mux_usecount--;
 		if (desc->mux_usecount)
 			return NULL;