Messages in this thread | | | Date | Mon, 31 Jul 2023 11:55:51 +0800 | Subject | Re: [PATCH V3 1/2] serial: sprd: Assign sprd_port after initialized to avoid wrong access | From | Baolin Wang <> |
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On 7/25/2023 2:40 PM, Chunyan Zhang wrote: > The global pointer 'sprd_port' may not zero when sprd_probe returns > failure, that is a risk for sprd_port to be accessed afterward, and > may lead to unexpected errors. > > For example: > > There are two UART ports, UART1 is used for console and configured in > kernel command line, i.e. "console="; > > The UART1 probe failed and the memory allocated to sprd_port[1] was > released, but sprd_port[1] was not set to NULL; > > In UART2 probe, the same virtual address was allocated to sprd_port[2], > and UART2 probe process finally will go into sprd_console_setup() to > register UART1 as console since it is configured as preferred console > (filled to console_cmdline[]), but the console parameters (sprd_port[1]) > belong to UART2. > > So move the sprd_port[] assignment to where the port already initialized > can avoid the above issue. > > Fixes: b7396a38fb28 ("tty/serial: Add Spreadtrum sc9836-uart driver support") > Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
LGTM. Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> --- > V3: > - Call uart_unregister_driver() only when the 'sprd_ports_num' decreases to 0; > - Add calling sprd_rx_free_buf() instread of sprd_remove() under clean_up lable. > > V2: > - Leave sprd_remove() to keep the unrelated code logic the same. > --- > drivers/tty/serial/sprd_serial.c | 25 +++++++++++++++++-------- > 1 file changed, 17 insertions(+), 8 deletions(-) > > diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c > index b58f51296ace..fc1377029021 100644 > --- a/drivers/tty/serial/sprd_serial.c > +++ b/drivers/tty/serial/sprd_serial.c > @@ -1106,7 +1106,7 @@ static bool sprd_uart_is_console(struct uart_port *uport) > static int sprd_clk_init(struct uart_port *uport) > { > struct clk *clk_uart, *clk_parent; > - struct sprd_uart_port *u = sprd_port[uport->line]; > + struct sprd_uart_port *u = container_of(uport, struct sprd_uart_port, port); > > clk_uart = devm_clk_get(uport->dev, "uart"); > if (IS_ERR(clk_uart)) { > @@ -1149,22 +1149,22 @@ static int sprd_probe(struct platform_device *pdev) > { > struct resource *res; > struct uart_port *up; > + struct sprd_uart_port *sport; > int irq; > int index; > int ret; > > index = of_alias_get_id(pdev->dev.of_node, "serial"); > - if (index < 0 || index >= ARRAY_SIZE(sprd_port)) { > + if (index < 0 || index >= UART_NR_MAX) { > dev_err(&pdev->dev, "got a wrong serial alias id %d\n", index); > return -EINVAL; > } > > - sprd_port[index] = devm_kzalloc(&pdev->dev, sizeof(*sprd_port[index]), > - GFP_KERNEL); > - if (!sprd_port[index]) > + sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL); > + if (!sport) > return -ENOMEM; > > - up = &sprd_port[index]->port; > + up = &sport->port; > up->dev = &pdev->dev; > up->line = index; > up->type = PORT_SPRD; > @@ -1195,7 +1195,7 @@ static int sprd_probe(struct platform_device *pdev) > * Allocate one dma buffer to prepare for receive transfer, in case > * memory allocation failure at runtime. > */ > - ret = sprd_rx_alloc_buf(sprd_port[index]); > + ret = sprd_rx_alloc_buf(sport); > if (ret) > return ret; > > @@ -1206,14 +1206,23 @@ static int sprd_probe(struct platform_device *pdev) > return ret; > } > } > + > sprd_ports_num++; > + sprd_port[index] = sport; > > ret = uart_add_one_port(&sprd_uart_driver, up); > if (ret) > - sprd_remove(pdev); > + goto clean_port; > > platform_set_drvdata(pdev, up); > > + return 0; > + > +clean_port: > + sprd_port[index] = NULL; > + if (--sprd_ports_num == 0) > + uart_unregister_driver(&sprd_uart_driver); > + sprd_rx_free_buf(sport); > return ret; > } >
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