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clk: zynq: Prevent null pointer dereference caused by kmalloc failure

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The kmalloc() in zynq_clk_setup() will return null if the
physical memory has run out. As a result, if we use snprintf()
to write data to the null address, the null pointer dereference
bug will happen.

This patch uses a stack variable to replace the kmalloc().

Fixes: 0ee52b157b ("clk: zynq: Add clock controller driver")
Suggested-by: Michal Simek <michal.simek@amd.com>
Suggested-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20240301084437.16084-1-duoming@zju.edu.cn
Acked-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Duoming Zhou 2024-03-01 16:44:37 +08:00 committed by Stephen Boyd
parent c1ab111e62
commit 7938e9ce39
1 changed files with 3 additions and 5 deletions
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8
drivers/clk/zynq/clkc.c
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@ -42,6 +42,7 @@ static void __iomem *zynq_clkc_base;
#define SLCR_SWDT_CLK_SEL (zynq_clkc_base + 0x204)
#define NUM_MIO_PINS 54
#define CLK_NAME_LEN 16
#define DBG_CLK_CTRL_CLKACT_TRC BIT(0)
#define DBG_CLK_CTRL_CPU_1XCLKACT BIT(1)
@ -215,7 +216,7 @@ static void __init zynq_clk_setup(struct device_node *np)
int i;
u32 tmp;
int ret;
char *clk_name;
char clk_name[CLK_NAME_LEN];
unsigned int fclk_enable = 0;
const char *clk_output_name[clk_max];
const char *cpu_parents[4];
@ -426,12 +427,10 @@ static void __init zynq_clk_setup(struct device_node *np)
"gem1_emio_mux", CLK_SET_RATE_PARENT,
SLCR_GEM1_CLK_CTRL, 0, 0, &gem1clk_lock);
tmp = strlen("mio_clk_00x");
clk_name = kmalloc(tmp, GFP_KERNEL);
for (i = 0; i < NUM_MIO_PINS; i++) {
int idx;
snprintf(clk_name, tmp, "mio_clk_%2.2d", i);
snprintf(clk_name, CLK_NAME_LEN, "mio_clk_%2.2d", i);
idx = of_property_match_string(np, "clock-names", clk_name);
if (idx >= 0)
can_mio_mux_parents[i] = of_clk_get_parent_name(np,
@ -439,7 +438,6 @@ static void __init zynq_clk_setup(struct device_node *np)
else
can_mio_mux_parents[i] = dummy_nm;
}
kfree(clk_name);
clk_register_mux(NULL, "can_mux", periph_parents, 4,
CLK_SET_RATE_NO_REPARENT, SLCR_CAN_CLK_CTRL, 4, 2, 0,
&canclk_lock);