linux-kernel - [PATCH 5/5] clk: at91: fix div by zero in USB clock driver

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Date:	Tue,  2 Sep 2014 09:50:18 +0200
From:	Boris BREZILLON <boris.brezillon@...e-electrons.com>
To:	Nicolas Ferre <nicolas.ferre@...el.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Andrew Victor <linux@...im.org.za>,
	Mike Turquette <mturquette@...aro.org>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Gaël PORTAY <gael.portay@...il.com>,
	Boris BREZILLON <boris.brezillon@...e-electrons.com>
Subject: [PATCH 5/5] clk: at91: fix div by zero in USB clock driver

Test rate value before calculating the div value to avoid div by zero.

Signed-off-by: Boris BREZILLON <boris.brezillon@...e-electrons.com>
Reported-by: Gaël PORTAY <gael.portay@...il.com>
---
 drivers/clk/at91/clk-usb.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c
index 1838777..24b5b02 100644
--- a/drivers/clk/at91/clk-usb.c
+++ b/drivers/clk/at91/clk-usb.c
@@ -279,10 +279,13 @@ static int at91rm9200_clk_usb_set_rate(struct clk_hw *hw, unsigned long rate,
 	int i;
 	struct at91rm9200_clk_usb *usb = to_at91rm9200_clk_usb(hw);
 	struct at91_pmc *pmc = usb->pmc;
-	unsigned long div = parent_rate / rate;
+	unsigned long div;
 
-	if (parent_rate % rate)
+	if (!rate || parent_rate % rate)
 		return -EINVAL;
+
+	div = parent_rate / rate;
+
 	for (i = 0; i < RM9200_USB_DIV_TAB_SIZE; i++) {
 		if (usb->divisors[i] == div) {
 			tmp = pmc_read(pmc, AT91_CKGR_PLLBR) &
-- 
1.9.1

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