This is a note to let you know that I've just added the patch titled i2c: mux: reg: check return value after calling platform_get_resource() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: i2c-mux-reg-check-return-value-after-calling-platfor.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 6430aef7b949ffc4d4ea5577782b90ad33c63dad Author: Yang Yingliang <yangyingliang@xxxxxxxxxx> Date: Sat Oct 29 17:38:25 2022 +0800 i2c: mux: reg: check return value after calling platform_get_resource() [ Upstream commit 2d47b79d2bd39cc6369eccf94a06568d84c906ae ] It will cause null-ptr-deref in resource_size(), if platform_get_resource() returns NULL, move calling resource_size() after devm_ioremap_resource() that will check 'res' to avoid null-ptr-deref. And use devm_platform_get_and_ioremap_resource() to simplify code. Fixes: b3fdd32799d8 ("i2c: mux: Add register-based mux i2c-mux-reg") Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx> Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/i2c/muxes/i2c-mux-reg.c b/drivers/i2c/muxes/i2c-mux-reg.c index b59a62f8d7a6..ac7971c776fa 100644 --- a/drivers/i2c/muxes/i2c-mux-reg.c +++ b/drivers/i2c/muxes/i2c-mux-reg.c @@ -187,13 +187,12 @@ static int i2c_mux_reg_probe(struct platform_device *pdev) if (!mux->data.reg) { 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); + mux->data.reg = devm_platform_get_and_ioremap_resource(pdev, 0, &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 &&