perf: Fix data race between pin_count increment/decrement

perf: Fix data race between pin_count increment/decrement

This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven.
This ID is fixed in Linux Kernel version v4.4.273 by commit 668bd53c549e1d6de8873c9037de98f042240b1e, it was introduced in version v2.6.39 by commit fe4b04fa31a6dcf4358aa84cf81e5a7fd079469b. For more details please see the references link.