CVE-2026-53234

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

net: ibm: emac: Fix use-after-free during device removal

The driver was using devmregisternetdev() which causes unregisternetdev() to be deferred until the devres cleanup phase, which runs after emacremove() returns. This creates a use-after-free window where:

1. emac_remove() is called, which tears down hardware (cancels work, detaches modules, unregisters from MAL)
2. emac_remove() returns
3. devres cleanup runs and finally calls unregister_netdev()

During step 3, the network stack might still process packets, triggering emacirq(), emacpoll(), or other handlers that access now-freed hardware resources (dev->emacp, dev->mal, etc.).

Fix this by replacing devmregisternetdev() with manual registernetdev() and calling unregisternetdev() at the beginning of emac_remove(), before any hardware teardown. This ensures the network device is fully stopped and unregistered before hardware resources are released.

The change is safe because: - dev->ndev is assigned very early in probe (before any error paths that could bypass emacremove) - platformsetdrvdata() is only called after successful registration, so emacremove() only runs for fully registered devices - unregister_netdev() is idempotent and safe to call on any registered device