In the Linux kernel, the following vulnerability has been resolved:
watchdog: pretimeout: Fix UAF in watchdog_unregister_governor()
When a watchdog governor is unregistered, it updates existing watchdog
devices that were using this governor by falling back to default_gov.
If the governor being unregistered is currently set as default_gov,
the default_gov is never cleared. This leads to 2 use-after-free
issues:
1. New watchdog devices registered after this point will inherit the
dangling default_gov.
2. Existing watchdog devices using the unregistered governor will have
their wdd->gov reassigned to the dangling default_gov.
Fix the UAF by clearing default_gov if it matches the governor being
unregistered.