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[01/32] rcu-tasks: Check for abandoned callbacks

Message ID	20220620225411.3842519-1-paulmck@kernel.org (mailing list archive)
State	Mainlined
Commit	4cf0585c4d663654fefa0b359f1908b5cd72802b
Headers	show Return-Path: <rcu-owner@kernel.org> From: "Paul E. McKenney" <paulmck@kernel.org> To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org> Subject: [PATCH rcu 01/32] rcu-tasks: Check for abandoned callbacks Date: Mon, 20 Jun 2022 15:53:40 -0700 Message-Id: <20220620225411.3842519-1-paulmck@kernel.org> In-Reply-To: <20220620225402.GA3842369@paulmck-ThinkPad-P17-Gen-1> References: <20220620225402.GA3842369@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	RCU Tasks updates for v5.20 \| expand [0/32] RCU Tasks updates for v5.20 [01/32] rcu-tasks: Check for abandoned callbacks [02/32] rcu-tasks: Split rcu_tasks_one_gp() from rcu_tasks_kthread() [03/32] rcu-tasks: Move synchronize_rcu_tasks_generic() down [04/32] rcu-tasks: Drive synchronous grace periods from calling task [05/32] rcu-tasks: Merge state into .b.need_qs and atomically update [06/32] rcu-tasks: Remove rcu_tasks_trace_postgp() wait for counter [07/32] rcu-tasks: Make trc_read_check_handler() fetch ->trc_reader_nesting only once [08/32] rcu-tasks: Idle tasks on offline CPUs are in quiescent states [09/32] rcu-tasks: Handle idle tasks for recently offlined CPUs [10/32] rcu-tasks: RCU Tasks Trace grace-period kthread has implicit QS [11/32] rcu-tasks: Make rcu_note_context_switch() unconditionally call rcu_tasks_qs() [12/32] rcu-tasks: Simplify trc_inspect_reader() QS logic [13/32] rcu-tasks: Add slow-IPI indicator to RCU Tasks Trace stall warnings [14/32] rcu-tasks: Flag offline CPUs in RCU Tasks Trace stall warnings [15/32] rcu-tasks: Make RCU Tasks Trace stall warnings print full .b.need_qs field [16/32] rcu-tasks: Make RCU Tasks Trace stall warning handle idle offline tasks [17/32] rcu-tasks: Add data structures for lightweight grace periods [18/32] rcu-tasks: Track blocked RCU Tasks Trace readers [19/32] rcu-tasks: Untrack blocked RCU Tasks Trace at reader end [20/32] rcu-tasks: Add blocked-task indicator to RCU Tasks Trace stall warnings [21/32] rcu-tasks: Move rcu_tasks_trace_pertask() before rcu_tasks_trace_pregp_step() [22/32] rcu-tasks: Avoid rcu_tasks_trace_pertask() duplicate list additions [23/32] rcu-tasks: Scan running tasks for RCU Tasks Trace readers [24/32] rcu-tasks: Pull in tasks blocked within RCU Tasks Trace readers [25/32] rcu-tasks: Stop RCU Tasks Trace from scanning idle tasks [26/32] rcu-tasks: Stop RCU Tasks Trace from scanning full tasks list [27/32] rcu-tasks: Maintain a count of tasks blocking RCU Tasks Trace grace period [28/32] rcu-tasks: Eliminate RCU Tasks Trace IPIs to online CPUs [29/32] rcu-tasks: Disable and enable CPU hotplug in same function [30/32] rcu-tasks: Update comments [31/32] rcu-tasks: Be more patient for RCU Tasks boot-time testing [32/32] rcu-tasks: Use delayed_work to delay rcu_tasks_verify_self_tests()

Commit Message

Paul E. McKenney June 20, 2022, 10:53 p.m. UTC

This commit adds a debugging scan for callbacks that got lost during a
callback-queueing transition.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tasks.h | 5 +++++
 1 file changed, 5 insertions(+)

diff mbox series

Patch

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 3925e32159b5a..b8690a412c5bf 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -439,6 +439,11 @@  static int rcu_tasks_need_gpcb(struct rcu_tasks *rtp)
 			WRITE_ONCE(rtp->percpu_dequeue_lim, 1);
 			pr_info("Completing switch %s to CPU-0 callback queuing.\n", rtp->name);
 		}
+		for (cpu = rtp->percpu_dequeue_lim; cpu < nr_cpu_ids; cpu++) {
+			struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);
+
+			WARN_ON_ONCE(rcu_segcblist_n_cbs(&rtpcp->cblist));
+		}
 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);
 	}