[ANNOUNCE] v4.18.7-rt5v4.18.7-rt5-patches

Dear RT folks!

I'm pleased to announce the v4.18.7-rt5 patch set.

Changes since v4.18.7-rt4:

  - Avoid a memory allocation with disabled interrupts in the "cached
    device tree" code

  - Avoid queuing a work item with disabled preemption in the "srcu"
    code.

  - The simple-work queue code used a constant shifted by zero. This is
    reported by smack as an error because it should have been a plain
    number (in function it is used). Reported by Dan Carpenter.

Known issues
     - A warning triggered in "rcu_note_context_switch" originated from
       SyS_timer_gettime(). The issue was always there, it is now
       visible. Reported by Grygorii Strashko and Daniel Wagner.

The delta patch against v4.18.7-rt4 is appended below and can be found here:

     https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.18/incr/patch-4.18.7-rt4-rt5.patch.xz

You can get this release via the git tree at:

    git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v4.18.7-rt5

The RT patch against v4.18.7 can be found here:

    https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.18/older/patch-4.18.7-rt5.patch.xz

The split quilt queue is available at:

    https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.18/older/patches-4.18.7-rt5.tar.xz

Sebastian

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

10 files changed, 170 insertions, 6 deletions

diff --git a/patches/efi-Allow-efi-runtime.patch b/patches/efi-Allow-efi-runtime.patch
index a7ec961bd4b8..a700ca2dbb67 100644
--- a/patches/efi-Allow-efi-runtime.patch
+++ b/patches/efi-Allow-efi-runtime.patch
@@ -1,4 +1,3 @@
-From 667af2f3d8ccf947fe7c9dac0b59b175963163ba Mon Sep 17 00:00:00 2001
 From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
 Date: Thu, 26 Jul 2018 15:06:10 +0200
 Subject: [PATCH] efi: Allow efi=runtime
diff --git a/patches/fscache-initialize-cookie-hash-table-raw-spinlocks.patch b/patches/fscache-initialize-cookie-hash-table-raw-spinlocks.patch
index a47b6ee7cabd..e9fe577eb752 100644
--- a/patches/fscache-initialize-cookie-hash-table-raw-spinlocks.patch
+++ b/patches/fscache-initialize-cookie-hash-table-raw-spinlocks.patch
@@ -1,4 +1,3 @@
-From 0277aff2b41aef9e2a6bd716ee0076036881334d Mon Sep 17 00:00:00 2001
 From: Clark Williams <williams@redhat.com>
 Date: Tue, 3 Jul 2018 13:34:30 -0500
 Subject: [PATCH] fscache: initialize cookie hash table raw spinlocks
diff --git a/patches/irqchip-gic-v3-its-Move-pending-table-allocation-to-.patch b/patches/irqchip-gic-v3-its-Move-pending-table-allocation-to-.patch
index f68f93c5512c..20b2bab359bf 100644
--- a/patches/irqchip-gic-v3-its-Move-pending-table-allocation-to-.patch
+++ b/patches/irqchip-gic-v3-its-Move-pending-table-allocation-to-.patch
@@ -1,4 +1,3 @@
-From 111e6bab739e34e1af72a6248e452ad85f2d216d Mon Sep 17 00:00:00 2001
 From: Marc Zyngier <marc.zyngier@arm.com>
 Date: Fri, 27 Jul 2018 13:38:54 +0100
 Subject: [PATCH] irqchip/gic-v3-its: Move pending table allocation to init
diff --git a/patches/localversion.patch b/patches/localversion.patch
index 03a80b8b0e80..72cdd2b3c760 100644
--- a/patches/localversion.patch
+++ b/patches/localversion.patch
@@ -10,4 +10,4 @@ Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
 --- /dev/null
 +++ b/localversion-rt
 @@ -0,0 +1 @@
-+-rt4
++-rt5
diff --git a/patches/of-allocate-free-phandle-cache-outside-of-the-devtre.patch b/patches/of-allocate-free-phandle-cache-outside-of-the-devtre.patch
new file mode 100644
index 000000000000..2a477a101630
--- /dev/null
+++ b/patches/of-allocate-free-phandle-cache-outside-of-the-devtre.patch
@@ -0,0 +1,77 @@
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 31 Aug 2018 14:16:30 +0200
+Subject: [PATCH] of: allocate / free phandle cache outside of the devtree_lock
+
+The phandle cache code allocates memory while holding devtree_lock which
+is a raw_spinlock_t. Memory allocation (and free()) is not possible on
+RT while a raw_spinlock_t is held.
+Invoke the kfree() and kcalloc() while the lock is dropped.
+
+Cc: Rob Herring <robh+dt@kernel.org>
+Cc: Frank Rowand <frowand.list@gmail.com>
+Cc: devicetree@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/of/base.c |   22 ++++++++++++++--------
+ 1 file changed, 14 insertions(+), 8 deletions(-)
+
+--- a/drivers/of/base.c
++++ b/drivers/of/base.c
+@@ -108,43 +108,49 @@ void of_populate_phandle_cache(void)
+ 	u32 cache_entries;
+ 	struct device_node *np;
+ 	u32 phandles = 0;
++	struct device_node **shadow;
+ 
+ 	raw_spin_lock_irqsave(&devtree_lock, flags);
+-
+-	kfree(phandle_cache);
++	shadow = phandle_cache;
+ 	phandle_cache = NULL;
+ 
+ 	for_each_of_allnodes(np)
+ 		if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
+ 			phandles++;
+ 
++	raw_spin_unlock_irqrestore(&devtree_lock, flags);
++
+ 	cache_entries = roundup_pow_of_two(phandles);
+ 	phandle_cache_mask = cache_entries - 1;
+ 
+-	phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
+-				GFP_ATOMIC);
+-	if (!phandle_cache)
+-		goto out;
++	kfree(shadow);
++	shadow = kcalloc(cache_entries, sizeof(*phandle_cache), GFP_KERNEL);
++
++	if (!shadow)
++		return;
++	raw_spin_lock_irqsave(&devtree_lock, flags);
++	phandle_cache = shadow;
+ 
+ 	for_each_of_allnodes(np)
+ 		if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
+ 			phandle_cache[np->phandle & phandle_cache_mask] = np;
+ 
+-out:
+ 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+ }
+ 
+ int of_free_phandle_cache(void)
+ {
+ 	unsigned long flags;
++	struct device_node **shadow;
+ 
+ 	raw_spin_lock_irqsave(&devtree_lock, flags);
+ 
+-	kfree(phandle_cache);
++	shadow = phandle_cache;
+ 	phandle_cache = NULL;
+ 
+ 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+ 
++	kfree(shadow);
+ 	return 0;
+ }
+ #if !defined(CONFIG_MODULES)
diff --git a/patches/random-Remove-preempt-disabled-region.patch b/patches/random-Remove-preempt-disabled-region.patch
index 03f604723c69..31d91dfc3fcb 100644
--- a/patches/random-Remove-preempt-disabled-region.patch
+++ b/patches/random-Remove-preempt-disabled-region.patch
@@ -1,4 +1,3 @@
-From 20690515ca3fd9baa92a3c915c74b14290fef13c Mon Sep 17 00:00:00 2001
 From: Ingo Molnar <mingo@elte.hu>
 Date: Fri, 3 Jul 2009 08:29:30 -0500
 Subject: [PATCH] random: Remove preempt disabled region
diff --git a/patches/rcu-Use-cpus_read_lock-while-looking-at-cpu_online_m.patch b/patches/rcu-Use-cpus_read_lock-while-looking-at-cpu_online_m.patch
new file mode 100644
index 000000000000..9401234fd536
--- /dev/null
+++ b/patches/rcu-Use-cpus_read_lock-while-looking-at-cpu_online_m.patch
@@ -0,0 +1,60 @@
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 10 Sep 2018 14:58:37 +0200
+Subject: [PATCH] rcu: Use cpus_read_lock() while looking at cpu_online_mask
+
+It was possible that sync_rcu_exp_select_cpus() enqueued something on
+CPU0 while CPU0 was offline. Such a work item wouldn't be processed
+until CPU0 gets back online. This problem was addressed in commit
+fcc6354365015 ("rcu: Make expedited GPs handle CPU 0 being offline"). I
+don't think the issue fully addressed.
+
+Assume grplo = 0 and grphi = 7 and sync_rcu_exp_select_cpus() is invoked
+on CPU1. The preempt_disable() section on CPU1 won't ensure that CPU0
+remains online between looking at cpu_online_mask and invoking
+queue_work_on() on CPU1.
+
+Use cpus_read_lock() to ensure that `cpu' is not going down between
+looking at cpu_online_mask at invoking queue_work_on() and waiting for
+its completion. It is added around the loop + flush_work() which is
+similar to work_on_cpu_safe() (and we can have multiple jobs running on
+NUMA systems).
+
+Fixes: fcc6354365015 ("rcu: Make expedited GPs handle CPU 0 being
+		      offline")
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/rcu/tree_exp.h |    4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/kernel/rcu/tree_exp.h
++++ b/kernel/rcu/tree_exp.h
+@@ -479,6 +479,7 @@ static void sync_rcu_exp_select_cpus(str
+ 	sync_exp_reset_tree(rsp);
+ 	trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("select"));
+ 
++	cpus_read_lock();
+ 	/* Schedule work for each leaf rcu_node structure. */
+ 	rcu_for_each_leaf_node(rsp, rnp) {
+ 		rnp->exp_need_flush = false;
+@@ -493,13 +494,11 @@ static void sync_rcu_exp_select_cpus(str
+ 			continue;
+ 		}
+ 		INIT_WORK(&rnp->rew.rew_work, sync_rcu_exp_select_node_cpus);
+-		preempt_disable();
+ 		cpu = cpumask_next(rnp->grplo - 1, cpu_online_mask);
+ 		/* If all offline, queue the work on an unbound CPU. */
+ 		if (unlikely(cpu > rnp->grphi))
+ 			cpu = WORK_CPU_UNBOUND;
+ 		queue_work_on(cpu, rcu_par_gp_wq, &rnp->rew.rew_work);
+-		preempt_enable();
+ 		rnp->exp_need_flush = true;
+ 	}
+ 
+@@ -507,6 +506,7 @@ static void sync_rcu_exp_select_cpus(str
+ 	rcu_for_each_leaf_node(rsp, rnp)
+ 		if (rnp->exp_need_flush)
+ 			flush_work(&rnp->rew.rew_work);
++	cpus_read_unlock();
+ }
+ 
+ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
diff --git a/patches/sched-Allow-pinned-user-tasks-to-be-awakened-to-the-.patch b/patches/sched-Allow-pinned-user-tasks-to-be-awakened-to-the-.patch
index d5fb1f398d04..070b32a3a09c 100644
--- a/patches/sched-Allow-pinned-user-tasks-to-be-awakened-to-the-.patch
+++ b/patches/sched-Allow-pinned-user-tasks-to-be-awakened-to-the-.patch
@@ -1,4 +1,3 @@
-From b3dac61f924ec6d4cc4c1e08498f80a88e6a6c69 Mon Sep 17 00:00:00 2001
 From: Mike Galbraith <efault@gmx.de>
 Date: Sun, 19 Aug 2018 08:28:35 +0200
 Subject: [PATCH] sched: Allow pinned user tasks to be awakened to the CPU they
diff --git a/patches/series b/patches/series
index 56d092ccbb98..41df8ad05f43 100644
--- a/patches/series
+++ b/patches/series
@@ -56,6 +56,7 @@ arm-unwind-use_raw_lock.patch
 cgroup-use-irqsave-in-cgroup_rstat_flush_locked.patch
 fscache-initialize-cookie-hash-table-raw-spinlocks.patch
 Drivers-hv-vmbus-include-header-for-get_irq_regs.patch
+rcu-Use-cpus_read_lock-while-looking-at-cpu_online_m.patch
 
 ############################################################
 # Ready for posting
@@ -71,6 +72,7 @@ efi-Allow-efi-runtime.patch
 ############################################################
 x86-efi-drop-task_lock-from-efi_switch_mm.patch
 arm64-KVM-compute_layout-before-altenates-are-applie.patch
+of-allocate-free-phandle-cache-outside-of-the-devtre.patch
 
 ###############################################################
 # Stuff broken upstream and upstream wants something different
@@ -193,6 +195,7 @@ x86-kvm-require-const-tsc-for-rt.patch
 pci-switchtec-Don-t-use-completion-s-wait-queue.patch
 wait.h-include-atomic.h.patch
 work-simple-Simple-work-queue-implemenation.patch
+work-simple-drop-a-shit-statement-in-SWORK_EVENT_PEN.patch
 completion-use-simple-wait-queues.patch
 fs-aio-simple-simple-work.patch
 genirq-do-not-invoke-the-affinity-callback-via-a-wor.patch
diff --git a/patches/work-simple-drop-a-shit-statement-in-SWORK_EVENT_PEN.patch b/patches/work-simple-drop-a-shit-statement-in-SWORK_EVENT_PEN.patch
new file mode 100644
index 000000000000..28dcceea5c58
--- /dev/null
+++ b/patches/work-simple-drop-a-shit-statement-in-SWORK_EVENT_PEN.patch
@@ -0,0 +1,29 @@
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 10 Sep 2018 18:00:31 +0200
+Subject: [PATCH] work-simple: drop a shit statement in SWORK_EVENT_PENDING
+
+Dan Carpenter reported
+| smatch warnings:
+|kernel/sched/swork.c:63 swork_kthread() warn: test_bit() takes a bit number
+
+This is not a bug because we shift by zero (and use the same value in
+both places).
+Nevertheless I'm dropping that shift by zero to keep smatch quiet.
+
+Cc: Daniel Wagner <daniel.wagner@siemens.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/swork.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/kernel/sched/swork.c
++++ b/kernel/sched/swork.c
+@@ -12,7 +12,7 @@
+ #include <linux/spinlock.h>
+ #include <linux/export.h>
+ 
+-#define SWORK_EVENT_PENDING     (1 << 0)
++#define SWORK_EVENT_PENDING     1
+ 
+ static DEFINE_MUTEX(worker_mutex);
+ static struct sworker *glob_worker;