On 7/11/2023 10:57 AM, Chunyan Zhang wrote:
On Mon, 10 Jul 2023 at 17:57, Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> wrote:
On 7/10/2023 4:03 PM, Chunyan Zhang wrote:
The global pointer 'sprd_port' maybe not zero when sprd_probe returns
fail, that is a risk for sprd_port to be accessed afterward, and will
lead unexpected errors.
For example:
There're two UART ports, UART1 is used for console and configured in kernel
command line, i.e. "console=";
The UART1 probe fail and the memory allocated to sprd_port[1] was released,
but sprd_port[1] was not set to NULL;
IMO, we should just set sprd_port[1] to be NULL, which seems simpler?
This patch just does like this indeed, in the label of 'clean_port'.
Adding a local variable instead of using global pointer (sprd_port[])
to store the virtual address allocated for sprd_port can avoid
overmany goto labels.
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])
actually belongs to UART2.
I'm confusing why the console parameters belongs to UART2? Since the
console_cmdline[] will specify the serial index, that belongs to UART1.
The same virtual address stored in sprd_port[1] was reallocated to
sprd_port[2] after the UART1 probe returned failure.
After more thinking, I understood your case. :)
But I see a nit in this patch, you added a 'clean_port' label to clear
the resource for the fail-probe-port instead of sprd_remove(), however
sprd_remove() will call sprd_rx_free_buf() to free the DMA buffer
originally. I know the 2nd patch will add it back, but patch 1 is not
git-bisect safe, right?
So I think you should also add sprd_rx_free_buf() under the 'clean_port'
label in patch 1, then patch 2 moves the sprd_rx_free_buf() to the
correct place.
Please correct me if I miss something.
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@xxxxxxxxxx>
---
drivers/tty/serial/sprd_serial.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index b58f51296ace..942808517393 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;
@@ -1208,12 +1208,20 @@ static int sprd_probe(struct platform_device *pdev)
}
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;
+ sprd_ports_num--;
+ uart_unregister_driver(&sprd_uart_driver);
return ret;
}
