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Message-Id: <20240910173110.31944-1-adiupina@astralinux.ru>
Date: Tue, 10 Sep 2024 20:31:10 +0300
From: Alexandra Diupina <adiupina@...ralinux.ru>
To: Andrew Lunn <andrew@...n.ch>
Cc: Alexandra Diupina <adiupina@...ralinux.ru>,
Gregory Clement <gregory.clement@...tlin.com>,
Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>,
linux-arm-kernel@...ts.infradead.org,
linux-clk@...r.kernel.org,
linux-kernel@...r.kernel.org,
lvc-project@...uxtesting.org
Subject: [PATCH v2] clk: mvebu: Prevent division by zero in clk_double_div_recalc_rate()
get_div() may return zero, so it is necessary to check
before calling DIV_ROUND_UP_ULL().
Return value of get_div() depends on reg1, reg2, shift1, shift2
fields of clk_double_div structure which are filled using the
PERIPH_DOUBLEDIV macro. This macro is called from the
PERIPH_CLK_FULL_DD and PERIPH_CLK_MUX_DD macros (the last 4 arguments).
It is not known exactly what values can be contained in the registers
at the addresses DIV_SEL0, DIV_SEL1, DIV_SEL2, so the final value of
div can be zero. Print an error message and return 0 in this case.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 8ca4746a78ab ("clk: mvebu: Add the peripheral clock driver for Armada 3700")
Signed-off-by: Alexandra Diupina <adiupina@...ralinux.ru>
---
v2: added explanations to the commit message and printing
of an error message when div==0
drivers/clk/mvebu/armada-37xx-periph.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/mvebu/armada-37xx-periph.c b/drivers/clk/mvebu/armada-37xx-periph.c
index 8701a58a5804..8e749a354ffc 100644
--- a/drivers/clk/mvebu/armada-37xx-periph.c
+++ b/drivers/clk/mvebu/armada-37xx-periph.c
@@ -343,7 +343,13 @@ static unsigned long clk_double_div_recalc_rate(struct clk_hw *hw,
div = get_div(double_div->reg1, double_div->shift1);
div *= get_div(double_div->reg2, double_div->shift2);
- return DIV_ROUND_UP_ULL((u64)parent_rate, div);
+ if (!div) {
+ pr_err("Can't recalculate the rate of clock %s\n",
+ hw->init->name);
+ return 0;
+ } else {
+ return DIV_ROUND_UP_ULL((u64)parent_rate, div);
+ }
}
static const struct clk_ops clk_double_div_ops = {
--
2.30.2
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