CVE-2025-38735

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

gve: prevent ethtool ops after shutdown

A crash can occur if an ethtool operation is invoked after shutdown() is called.

shutdown() is invoked during system shutdown to stop DMA operations without performing expensive deallocations. It is discouraged to unregister the netdev in this path, so the device may still be visible to userspace and kernel helpers.

In gve, shutdown() tears down most internal data structures. If an ethtool operation is dispatched after shutdown(), it will dereference freed or NULL pointers, leading to a kernel panic. While graceful shutdown normally quiesces userspace before invoking the reboot syscall, forced shutdowns (as observed on GCP VMs) can still trigger this path.

Fix by calling netif_device_detach() in shutdown(). This marks the device as detached so the ethtool ioctl handler will skip dispatching operations to the driver.

After gve invokes shutdown() (e.g., during system/VM shutdown), most internal structures are torn down but the netdev may remain visible, so subsequent ethtool operations can dereference freed/NULL pointers and crash the kernel. Privilege escalation is considered highly unrealistic in this case, as the bug only manifests during system shutdown.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.