Merge tag 'urgent-rcu.2024.01.24a' of https://github.com/neeraju/linux

Merge tag 'urgent-rcu.2024.01.24a' of https://github.com/neeraju/linux

Pull RCU fix from Neeraj Upadhyay:
 "This fixes RCU grace period stalls, which are observed when an
  outgoing CPU's quiescent state reporting results in wakeup of one of
  the grace period kthreads, to complete the grace period.

  If those kthreads have SCHED_FIFO policy, the wake up can indirectly
  arm the RT bandwith timer to the local offline CPU.

  Earlier migration of the hrtimers from the CPU introduced in commit
  5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU
  earlier") results in this timer getting ignored.

  If the RCU grace period kthreads are waiting for RT bandwidth to be
  available, they may never be actually scheduled, resulting in RCU
  stall warnings"

* tag 'urgent-rcu.2024.01.24a' of https://github.com/neeraju/linux:
  rcu: Defer RCU kthreads wakeup when CPU is dying