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From: Frederic Weisbecker <frederic@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Neeraj Upadhyay <neeraj.upadhyay@amd.com>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Uladzislau Rezki <urezki@gmail.com>,
	Zqiang <qiang.zhang1211@gmail.com>, rcu <rcu@vger.kernel.org>
Subject: [PATCH 0/3] rcu: Fix yet another wake up from offline related issue
Date: Wed,  2 Oct 2024 16:57:35 +0200	[thread overview]
Message-ID: <20241002145738.38226-1-frederic@kernel.org> (raw)

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(-)

-- 
2.46.0


             reply	other threads:[~2024-10-02 14:57 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-02 14:57 Frederic Weisbecker [this message]
2024-10-02 14:57 ` [PATCH 1/3] rcu/nocb: Use switch/case on NOCB timer state machine Frederic Weisbecker
2024-10-10  8:16   ` Boqun Feng
2024-10-10 12:55     ` Frederic Weisbecker
2024-10-02 14:57 ` [PATCH 2/3] rcu/nocb: Fix rcuog wake-up from offline softirq Frederic Weisbecker
2024-10-09 18:23   ` Joel Fernandes
2024-10-09 20:56     ` Frederic Weisbecker
2024-10-10  0:27       ` Joel Fernandes
2024-10-02 14:57 ` [PATCH 3/3] rcu: Report callbacks enqueued on offline CPU blind spot Frederic Weisbecker
2024-10-02 15:00   ` Frederic Weisbecker
2024-10-09  2:03     ` Paul E. McKenney
2024-10-09 15:13       ` Paul E. McKenney
2024-10-10 14:30         ` Joel Fernandes
2024-10-09  2:24     ` Neeraj Upadhyay

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