pinctrl: mediatek: fix global-out-of-bounds issue

stable inclusion
from stable-v5.10.89
commit 441d3873664d170982922c5d2fc01fa89d9439ed
bugzilla: 186140 https://gitee.com/openeuler/kernel/issues/I4S8HA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=441d3873664d170982922c5d2fc01fa89d9439ed

--------------------------------

commit 2d5446da upstream.

When eint virtual eint number is greater than gpio number,
it maybe produce 'desc[eint_n]' size globle-out-of-bounds issue.
Signed-off-by: NGuodong Liu <guodong.liu@mediatek.corp-partner.google.com>
Signed-off-by: NZhiyong Tao <zhiyong.tao@mediatek.com>
Reviewed-by: NChen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20211110071900.4490-2-zhiyong.tao@mediatek.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c

@@ -280,8 +280,12 @@ static int mtk_xt_get_gpio_n(void *data, unsigned long eint_n,
 	desc = (const struct mtk_pin_desc *)hw->soc->pins;
 	*gpio_chip = &hw->chip;
 
-	/* Be greedy to guess first gpio_n is equal to eint_n */
-	if (desc[eint_n].eint.eint_n == eint_n)
+	/*
+	 * Be greedy to guess first gpio_n is equal to eint_n.
+	 * Only eint virtual eint number is greater than gpio number.
+	 */
+	if (hw->soc->npins > eint_n &&
+	    desc[eint_n].eint.eint_n == eint_n)
 		*gpio_n = eint_n;
 	else
 		*gpio_n = mtk_xt_find_eint_num(hw, eint_n);