Adding debian version 4.19.249-2.debian/4.19.249-2debian

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 96 insertions, 0 deletions

diff --git a/debian/patches-rt/0161-srcu-use-cpu_online-instead-custom-check.patch b/debian/patches-rt/0161-srcu-use-cpu_online-instead-custom-check.patch
new file mode 100644
index 000000000..626188f7a
--- /dev/null
+++ b/debian/patches-rt/0161-srcu-use-cpu_online-instead-custom-check.patch
@@ -0,0 +1,96 @@
+From 4ce509b22af5e28f62c90f342169dad726731a39 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 13 Sep 2017 14:43:41 +0200
+Subject: [PATCH 161/347] srcu: use cpu_online() instead custom check
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+The current check via srcu_online is slightly racy because after looking
+at srcu_online there could be an interrupt that interrupted us long
+enough until the CPU we checked against went offline.
+An alternative would be to hold the hotplug rwsem (so the CPUs don't
+change their state) and then check based on cpu_online() if we queue it
+on a specific CPU or not. queue_work_on() itself can handle if something
+is enqueued on an offline CPU but a timer which is enqueued on an offline
+CPU won't fire until the CPU is back online.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/rcu/srcutree.c | 22 ++++------------------
+ kernel/rcu/tree.c     |  4 ----
+ 2 files changed, 4 insertions(+), 22 deletions(-)
+
+diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
+index 1ff17e297f0c..df0375453ba1 100644
+--- a/kernel/rcu/srcutree.c
++++ b/kernel/rcu/srcutree.c
+@@ -38,6 +38,7 @@
+ #include <linux/delay.h>
+ #include <linux/module.h>
+ #include <linux/srcu.h>
++#include <linux/cpu.h>
+ 
+ #include "rcu.h"
+ #include "rcu_segcblist.h"
+@@ -460,21 +461,6 @@ static void srcu_gp_start(struct srcu_struct *sp)
+ 	WARN_ON_ONCE(state != SRCU_STATE_SCAN1);
+ }
+ 
+-/*
+- * Track online CPUs to guide callback workqueue placement.
+- */
+-DEFINE_PER_CPU(bool, srcu_online);
+-
+-void srcu_online_cpu(unsigned int cpu)
+-{
+-	WRITE_ONCE(per_cpu(srcu_online, cpu), true);
+-}
+-
+-void srcu_offline_cpu(unsigned int cpu)
+-{
+-	WRITE_ONCE(per_cpu(srcu_online, cpu), false);
+-}
+-
+ /*
+  * Place the workqueue handler on the specified CPU if online, otherwise
+  * just run it whereever.  This is useful for placing workqueue handlers
+@@ -486,12 +472,12 @@ static bool srcu_queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
+ {
+ 	bool ret;
+ 
+-	preempt_disable();
+-	if (READ_ONCE(per_cpu(srcu_online, cpu)))
++	cpus_read_lock();
++	if (cpu_online(cpu))
+ 		ret = queue_delayed_work_on(cpu, wq, dwork, delay);
+ 	else
+ 		ret = queue_delayed_work(wq, dwork, delay);
+-	preempt_enable();
++	cpus_read_unlock();
+ 	return ret;
+ }
+ 
+diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
+index ae716ca783bc..f162a4f54b05 100644
+--- a/kernel/rcu/tree.c
++++ b/kernel/rcu/tree.c
+@@ -3784,8 +3784,6 @@ int rcutree_online_cpu(unsigned int cpu)
+ 		rnp->ffmask |= rdp->grpmask;
+ 		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+ 	}
+-	if (IS_ENABLED(CONFIG_TREE_SRCU))
+-		srcu_online_cpu(cpu);
+ 	if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
+ 		return 0; /* Too early in boot for scheduler work. */
+ 	sync_sched_exp_online_cleanup(cpu);
+@@ -3813,8 +3811,6 @@ int rcutree_offline_cpu(unsigned int cpu)
+ 	}
+ 
+ 	rcutree_affinity_setting(cpu, cpu);
+-	if (IS_ENABLED(CONFIG_TREE_SRCU))
+-		srcu_offline_cpu(cpu);
+ 	return 0;
+ }
+ 
+-- 
+2.36.1
+