In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix DM I2C teardown race DM I2C adapters can remain visible to userspace while DM teardown is already in progress

Overview

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

drm/amd/display: Fix DM I2C teardown race

DM I2C adapters can remain visible to userspace while DM teardown is already in progress. A concurrent i2c-dev transfer may then enter amdgpu_dm_i2c_xfer() after the backing DM state has been torn down, leading to a NULL pointer dereference.

Create a devres group around the DM I2C adapter lifetime and release it at the start of dm_hw_fini(), before HPD, IRQ, and DM state are torn down. This removes the I2C adapters first and waits for in-flight users to drain before the structures used by amdgpu_dm_i2c_xfer() disappear.

This fixes a teardown ordering race seen during device removal:

BUG: kernel NULL pointer dereference RIP: amdgpu_dm_i2c_xfer+0x122/0x1c0 [amdgpu] Call Trace: __i2c_transfer i2c_transfer i2cdev_ioctl_rdwr

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.