CVE-2025-21685

In the Linux kernel, the following vulnerability has been resolved:

platform/x86: lenovo-yoga-tab2-pro-1380-fastcharger: fix serdev race

The yt2_1380_fc_serdev_probe() function calls 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 controllers receive_buf handler, as it assumes serdev->ops is valid when SERPORT_ACTIVE is set.

This is similar to the issue fixed in commit 5e700b384ec1 (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 devm_serdev_device_open().

Note, serdev_device_set_baudrate() and serdev_device_set_flow_control() calls should be after the devm_serdev_device_open() call.

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/3f67e07873df3c6d9ce2582260b83732e1d3a40b
• https://git.kernel.org/stable/c/59616a91e5e74833b2008b56c66879857c616006