[PATCH 5.4 286/411] tty: serial: fsl_lpuart: fix potential bug when using both of_alias_get_id and ida_simple_get

Greg Kroah-Hartman
2022-06-13T11:34:59Z

From: Sherry Sun <sherry.sun@nxp.com>

[ Upstream commit f398e0aa325c61fa20903833a5b534ecb8e6e418 ]

Now fsl_lpuart driver use both of_alias_get_id() and ida_simple_get() in
.probe(), which has the potential bug. For example, when remove the
lpuart7 alias in dts, of_alias_get_id() will return error, then call
ida_simple_get() to allocate the id 0 for lpuart7, this may confilct
with the lpuart4 which has alias 0.

aliases {
...
serial0 = &lpuart4;
serial1 = &lpuart5;
serial2 = &lpuart6;
serial3 = &lpuart7;
}

So remove the ida_simple_get() in .probe(), return an error directly
when calling of_alias_get_id() fails, which is consistent with other
uart drivers behavior.

Fixes: 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node dependence")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220321112211.8895-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/fsl_lpuart.c | 24 ++++--------------------
1 file changed, 4 insertions(+), 20 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 13e705b53217..4bdc12908146 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -233,8 +233,6 @@
/* IMX lpuart has four extra unused regs located at the beginning */
#define IMX_REG_OFF 0x10

-static DEFINE_IDA(fsl_lpuart_ida);
-
enum lpuart_type {
VF610_LPUART,
LS1021A_LPUART,
@@ -269,7 +267,6 @@ struct lpuart_port {
int rx_dma_rng_buf_len;
unsigned int dma_tx_nents;
wait_queue_head_t dma_wait;
- bool id_allocated;
};

struct lpuart_soc_data {
@@ -2450,23 +2447,18 @@ static int lpuart_probe(struct platform_device *pdev)

ret = of_alias_get_id(np, "serial");
if (ret < 0) {
- ret = ida_simple_get(&fsl_lpuart_ida, 0, UART_NR, GFP_KERNEL);
- if (ret < 0) {
- dev_err(&pdev->dev, "port line is full, add device failed\n");
- return ret;
- }
- sport->id_allocated = true;
+ dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
+ return ret;
}
if (ret >= ARRAY_SIZE(lpuart_ports)) {
dev_err(&pdev->dev, "serial%d out of range\n", ret);
- ret = -EINVAL;
- goto failed_out_of_range;
+ return -EINVAL;
}
sport->port.line = ret;

ret = lpuart_enable_clks(sport);
if (ret)
- goto failed_clock_enable;
+ return ret;
sport->port.uartclk = lpuart_get_baud_clk_rate(sport);

lpuart_ports[sport->port.line] = sport;
@@ -2516,10 +2508,6 @@ static int lpuart_probe(struct platform_device *pdev)
failed_attach_port:
failed_irq_request:
lpuart_disable_clks(sport);
-failed_clock_enable:
-failed_out_of_range:
- if (sport->id_allocated)
- ida_simple_remove(&fsl_lpuart_ida, sport->port.line);
return ret;
}

@@ -2529,9 +2517,6 @@ static int lpuart_remove(struct platform_device *pdev)

uart_remove_one_port(&lpuart_reg, &sport->port);

- if (sport->id_allocated)
- ida_simple_remove(&fsl_lpuart_ida, sport->port.line);
-
lpuart_disable_clks(sport);

if (sport->dma_tx_chan)
@@ -2663,7 +2648,6 @@ static int __init lpuart_serial_init(void)

static void __exit lpuart_serial_exit(void)
{
- ida_destroy(&fsl_lpuart_ida);
platform_driver_unregister(&lpuart_driver);
uart_unregister_driver(&lpuart_reg);
}
--
2.35.1