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

From: Frederic Weisbecker
Date: Wed Oct 02 2024 - 10:57:58 EST


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@xxxxxxxxx

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(-)

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2.46.0