linux-kernel - [PATCH v2] clk:mmp: clk-mix.c fix divide-by-zero

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Date:   Sat, 30 Mar 2019 09:27:14 +0800
From:   nixiaoming <nixiaoming@...wei.com>
To:     <mturquette@...libre.com>, <sboyd@...nel.org>,
        <nixiaoming@...wei.com>, <chao.xie@...vell.com>,
        <mojha@...eaurora.org>
CC:     <linux-clk@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] clk:mmp: clk-mix.c fix divide-by-zero

The _get_div function has a branch with a return value of 0
Add a check on the return value of _get_div to avoid divide-by-zero

Signed-off-by: nixiaoming <nixiaoming@...wei.com>
Reviewed-by: Mukesh Ojha <mojha@...eaurora.org>
---
 drivers/clk/mmp/clk-mix.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/clk/mmp/clk-mix.c b/drivers/clk/mmp/clk-mix.c
index 90814b2..6ed5ad7 100644
--- a/drivers/clk/mmp/clk-mix.c
+++ b/drivers/clk/mmp/clk-mix.c
@@ -245,6 +245,9 @@ static int mmp_clk_mix_determine_rate(struct clk_hw *hw,
 			div_val_max = _get_maxdiv(mix);
 			for (j = 0; j < div_val_max; j++) {
 				div = _get_div(mix, j);
+				/* avoid divide-by-zero */
+				if (!div)
+					continue;
 				mix_rate = parent_rate / div;
 				gap = abs(mix_rate - req->rate);
 				if (!parent_best || gap < gap_best) {
@@ -341,6 +344,9 @@ static unsigned long mmp_clk_mix_recalc_rate(struct clk_hw *hw,
 	shift = mix->reg_info.shift_div;
 
 	div = _get_div(mix, MMP_CLK_BITS_GET_VAL(mux_div, width, shift));
+	/* avoid divide-by-zero */
+	if (!div)
+		return -EINVAL;
 
 	return parent_rate / div;
 }
-- 
1.8.5.6