It will cause null-ptr-deref when resource_size(res) invoked,
if platform_get_resource() returns NULL.

Fixes: b3fdd32799d8 ("i2c: mux: Add register-based mux i2c-mux-reg")
Signed-off-by: Hui Tang <tanghui20@huawei.com>
---
 drivers/i2c/muxes/i2c-mux-reg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/muxes/i2c-mux-reg.c b/drivers/i2c/muxes/i2c-mux-reg.c
index 0e0679f65cf7..d26de1017385 100644
--- a/drivers/i2c/muxes/i2c-mux-reg.c
+++ b/drivers/i2c/muxes/i2c-mux-reg.c
@@ -184,12 +184,12 @@ static int i2c_mux_reg_probe(struct platform_device *pdev)
 		dev_info(&pdev->dev,
 			"Register not set, using platform resource\n");
 		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-		mux->data.reg_size = resource_size(res);
 		mux->data.reg = devm_ioremap_resource(&pdev->dev, res);
 		if (IS_ERR(mux->data.reg)) {
 			ret = PTR_ERR(mux->data.reg);
 			goto err_put_parent;
 		}
+		mux->data.reg_size = resource_size(res);
 	}
 
 	if (mux->data.reg_size != 4 && mux->data.reg_size != 2 &&
-- 
2.17.1

On Mon, Nov 14, 2022 at 08:43:22AM +0800, Hui Tang wrote:
> It will cause null-ptr-deref when resource_size(res) invoked,
> if platform_get_resource() returns NULL.
> 
> Fixes: b3fdd32799d8 ("i2c: mux: Add register-based mux i2c-mux-reg")
> Signed-off-by: Hui Tang <tanghui20@huawei.com>

Correct, yet I applied this older patch instead:

http://patchwork.ozlabs.org/project/linux-i2c/patch/20221029093825.3425857-1-yangyingliang@huawei.com/