Commit 0dd6770a authored by Chenyuan Yang's avatar Chenyuan Yang Committed by Krzysztof Kozlowski
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w1: fix NULL pointer dereference in probe 



The w1_uart_probe() function calls w1_uart_serdev_open() (which includes
devm_serdev_device_open()) before setting the client ops via
serdev_device_set_client_ops(). This ordering can trigger a NULL pointer
dereference in the serdev controller's receive_buf handler, as it assumes
serdev->ops is valid when SERPORT_ACTIVE is set.

This is similar to the issue fixed in commit 5e700b38
("platform/chrome: cros_ec_uart: properly fix race condition") where
devm_serdev_device_open() was called before fully initializing the
device.

Fix the race by ensuring client ops are set before enabling the port via
w1_uart_serdev_open().

Fixes: a3c08804 ("w1: add UART w1 bus driver")
Signed-off-by: default avatarChenyuan Yang <chenyuan0y@gmail.com>
Acked-by: default avatarChristoph Winklhofer <cj.winklhofer@gmail.com>
Link: https://lore.kernel.org/r/20250111181803.2283611-1-chenyuan0y@gmail.com


Signed-off-by: default avatarKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
parent 2014c95a

drivers/w1/masters/w1-uart.c

+2 −2
Original line number Diff line number Diff line
@@ -372,11 +372,11 @@ static int w1_uart_probe(struct serdev_device *serdev) 
	init_completion(&w1dev->rx_byte_received);

	mutex_init(&w1dev->rx_mutex);



	serdev_device_set_drvdata(serdev, w1dev);

	serdev_device_set_client_ops(serdev, &w1_uart_serdev_ops);

	ret = w1_uart_serdev_open(w1dev);

	if (ret < 0)

		return ret;

	serdev_device_set_drvdata(serdev, w1dev);

	serdev_device_set_client_ops(serdev, &w1_uart_serdev_ops);



	return w1_add_master_device(&w1dev->bus);

}