aio: Fix null ptr deref in aio_complete() wakeup

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: aio: Fix null ptr deref in aio_complete() wakeup list_del_init_careful() needs to be the last access to the wait queue entry - it effectively unlocks access. Previously, finish_wait() would see the empty list head and skip taking the lock, and then we'd return - but the completion path would still attempt to do the wakeup after the task_struct pointer had been overwritten.

References

• https://git.kernel.org/stable/c/9678bcc6234d83759fe091c197f5017a32b468da
• https://git.kernel.org/stable/c/caeb4b0a11b3393e43f7fa8e0a5a18462acc66bd