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[0/3] rcu: Fix yet another wake up from offline related issue

Message ID 20241002145738.38226-1-frederic@kernel.org (mailing list archive)
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Series rcu: Fix yet another wake up from offline related issue | expand

Message

Frederic Weisbecker Oct. 2, 2024, 2:57 p.m. UTC 
Hi,

A new warning has been reported due to swake_up_one_online() use
from an offline IRQ:

	https://lore.kernel.org/oe-lkp/202409231644.4c55582d-lkp@intel.com

Here is a tentative fix.

Similar issue can happen with exp kthread and GP kthread if offline tick
fires and there is a pending deferred quiescent state to report on
PREEMPT_RCU. Currently only oneshot ticks are disabled while the CPU is
offlining. I have yet to take care of the periodic tick implementation.
Work in progress...

Frederic Weisbecker (3):
  rcu/nocb: Use switch/case on NOCB timer state machine
  rcu/nocb: Fix rcuog wake-up from offline softirq
  rcu: Report callbacks enqueued on offline CPU blind spot

 kernel/rcu/tree.c      |  3 +++
 kernel/rcu/tree.h      |  1 +
 kernel/rcu/tree_nocb.h | 47 +++++++++++++++++++++++++++++++-----------
 3 files changed, 39 insertions(+), 12 deletions(-)