thunderbolt: Hold a router reference for each allocated HopID

Summary

In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Hold a router reference for each allocated HopID tb_stop() drops the reference to all DP tunnels but does not deactivate them, thus nothing cancels a dprx_work still in flight (which holds its own tunnel reference) and the tunnel can outlive tb_switch_remove(). The HopID releases in tb_path_free() then operate on freed IDAs and trigger warnings like ida_free called for id=8 which is not allocated. This can be triggered by unbinding the driver while a DP tunnel is still waiting for the DPRX capabilities read to finish. On the Apple NHI unplugging the cable runs into just that reliably because the read can never finish right now and because the unplug powers down the entire USB4 complex and removes the NHI device. Take a router reference whenever an input or output HopID is allocated and drop it again after the HopID is released. This keeps the ports and their HopID IDAs alive for as long as they are used. The KUnit tests allocate routers without ever registering their devices so initialize the embedded struct device there as well and drop its initial reference when the test is finished.

Timeline

1. Oct 18, 2026, 3:46 PM UTCCVE published
2. Oct 19, 2026, 9:24 AM UTCRecord last updated

Affected versions

• Linux Linux

  From d6d458d42e1e1544a18f37f1d5c840e00d5261b9 · fixed in c444d2c17dc236680324fd989232199680a6c419; From d6d458d42e1e1544a18f37f1d5c840e00d5261b9 · fixed in 2b5f976119d8f099a03cbf700df3d9c8690fe33d; From d6d458d42e1e1544a18f37f1d5c840e00d5261b9 · fixed in 032c59c7681c661b63123231824170c025afb7e7

• Linux Linux

  6.14

• KernelLinux

  From 6.14.0 · fixed in 6.18.56; From 6.19.0 · fixed in 7.2.10

References 3