Linux · Linux Kernel · CVE-2021-47318
**Name of the Vulnerable Software and Affected Versions**
Linux kernel (affected versions not specified)
**Description**
The issue is related to a use-after-free vulnerability in the arch topology component of the Linux kernel. The `topology scale freq tick()` function, which is called from `scheduler tick()`, may use a pointer to `struct scale freq data` that was previously cleared by `topology clear scale freq source()`. To resolve this, the RCU update mechanism is used to guarantee race-free updates. The `synchronize rcu()` function ensures that all RCU critical sections started before it is called will finish before it returns, allowing the callers of `topology clear scale freq source()` to free related resources without worrying about their callback being called again.
**Recommendations**
At the moment, there is no information about a newer version that contains a fix for this vulnerability.