md: fix rcu protection in md_wakeup_thread

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: md: fix rcu protection in md_wakeup_thread We attempted to use RCU to protect the pointer 'thread', but directly passed the value when calling md_wakeup_thread(). This means that the RCU pointer has been acquired before rcu_read_lock(), which renders rcu_read_lock() ineffective and could lead to a use-after-free.

References

• https://git.kernel.org/stable/c/21989cb5034c835b212385a2afadf279d8069da0
• https://git.kernel.org/stable/c/a4bd1caf591faeae44cb10b6517e7dacb5139bda
• https://git.kernel.org/stable/c/f98b191f78124405294481dea85f8a22a3eb0a59
• https://git.kernel.org/stable/c/0dc76205549b4c25705e54345f211b9f66e018a0