Update Linux to v5.4.148
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz
Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index bc2e09a..885d479 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -50,6 +50,7 @@
#include <linux/uaccess.h>
#include <linux/sched/isolation.h>
#include <linux/nmi.h>
+#include <linux/kvm_para.h>
#include "workqueue_internal.h"
@@ -425,7 +426,8 @@
* ignored.
*/
#define for_each_pwq(pwq, wq) \
- list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node) \
+ list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node, \
+ lockdep_is_held(&wq->mutex)) \
if (({ assert_rcu_or_wq_mutex(wq); false; })) { } \
else
@@ -863,7 +865,8 @@
* @task: task going to sleep
*
* This function is called from schedule() when a busy worker is
- * going to sleep.
+ * going to sleep. Preemption needs to be disabled to protect ->sleeping
+ * assignment.
*/
void wq_worker_sleeping(struct task_struct *task)
{
@@ -880,7 +883,8 @@
pool = worker->pool;
- if (WARN_ON_ONCE(worker->sleeping))
+ /* Return if preempted before wq_worker_running() was reached */
+ if (worker->sleeping)
return;
worker->sleeping = 1;
@@ -1408,7 +1412,6 @@
*/
lockdep_assert_irqs_disabled();
- debug_work_activate(work);
/* if draining, only works from the same workqueue are allowed */
if (unlikely(wq->flags & __WQ_DRAINING) &&
@@ -1416,14 +1419,16 @@
return;
rcu_read_lock();
retry:
- if (req_cpu == WORK_CPU_UNBOUND)
- cpu = wq_select_unbound_cpu(raw_smp_processor_id());
-
/* pwq which will be used unless @work is executing elsewhere */
- if (!(wq->flags & WQ_UNBOUND))
- pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
- else
+ if (wq->flags & WQ_UNBOUND) {
+ if (req_cpu == WORK_CPU_UNBOUND)
+ cpu = wq_select_unbound_cpu(raw_smp_processor_id());
pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
+ } else {
+ if (req_cpu == WORK_CPU_UNBOUND)
+ cpu = raw_smp_processor_id();
+ pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
+ }
/*
* If @work was previously on a different pool, it might still be
@@ -1488,6 +1493,7 @@
worklist = &pwq->delayed_works;
}
+ debug_work_activate(work);
insert_work(pwq, work, worklist, work_flags);
out:
@@ -1843,12 +1849,6 @@
mutex_lock(&wq_pool_attach_mutex);
/*
- * set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
- * online CPUs. It'll be re-applied when any of the CPUs come up.
- */
- set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
-
- /*
* The wq_pool_attach_mutex ensures %POOL_DISASSOCIATED remains
* stable across this function. See the comments above the flag
* definition for details.
@@ -1856,6 +1856,9 @@
if (pool->flags & POOL_DISASSOCIATED)
worker->flags |= WORKER_UNBOUND;
+ if (worker->rescue_wq)
+ set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
+
list_add_tail(&worker->node, &pool->workers);
worker->pool = pool;
@@ -2532,8 +2535,14 @@
*/
if (need_to_create_worker(pool)) {
spin_lock(&wq_mayday_lock);
- get_pwq(pwq);
- list_move_tail(&pwq->mayday_node, &wq->maydays);
+ /*
+ * Queue iff we aren't racing destruction
+ * and somebody else hasn't queued it already.
+ */
+ if (wq->rescuer && list_empty(&pwq->mayday_node)) {
+ get_pwq(pwq);
+ list_add_tail(&pwq->mayday_node, &wq->maydays);
+ }
spin_unlock(&wq_mayday_lock);
}
}
@@ -3651,15 +3660,21 @@
unbound_release_work);
struct workqueue_struct *wq = pwq->wq;
struct worker_pool *pool = pwq->pool;
- bool is_last;
+ bool is_last = false;
- if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
- return;
+ /*
+ * when @pwq is not linked, it doesn't hold any reference to the
+ * @wq, and @wq is invalid to access.
+ */
+ if (!list_empty(&pwq->pwqs_node)) {
+ if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
+ return;
- mutex_lock(&wq->mutex);
- list_del_rcu(&pwq->pwqs_node);
- is_last = list_empty(&wq->pwqs);
- mutex_unlock(&wq->mutex);
+ mutex_lock(&wq->mutex);
+ list_del_rcu(&pwq->pwqs_node);
+ is_last = list_empty(&wq->pwqs);
+ mutex_unlock(&wq->mutex);
+ }
mutex_lock(&wq_pool_mutex);
put_unbound_pool(pool);
@@ -3707,17 +3722,24 @@
* is updated and visible.
*/
if (!freezable || !workqueue_freezing) {
+ bool kick = false;
+
pwq->max_active = wq->saved_max_active;
while (!list_empty(&pwq->delayed_works) &&
- pwq->nr_active < pwq->max_active)
+ pwq->nr_active < pwq->max_active) {
pwq_activate_first_delayed(pwq);
+ kick = true;
+ }
/*
* Need to kick a worker after thawed or an unbound wq's
- * max_active is bumped. It's a slow path. Do it always.
+ * max_active is bumped. In realtime scenarios, always kicking a
+ * worker will cause interference on the isolated cpu cores, so
+ * let's kick iff work items were activated.
*/
- wake_up_worker(pwq->pool);
+ if (kick)
+ wake_up_worker(pwq->pool);
} else {
pwq->max_active = 0;
}
@@ -4325,9 +4347,29 @@
struct pool_workqueue *pwq;
int node;
+ /*
+ * Remove it from sysfs first so that sanity check failure doesn't
+ * lead to sysfs name conflicts.
+ */
+ workqueue_sysfs_unregister(wq);
+
/* drain it before proceeding with destruction */
drain_workqueue(wq);
+ /* kill rescuer, if sanity checks fail, leave it w/o rescuer */
+ if (wq->rescuer) {
+ struct worker *rescuer = wq->rescuer;
+
+ /* this prevents new queueing */
+ spin_lock_irq(&wq_mayday_lock);
+ wq->rescuer = NULL;
+ spin_unlock_irq(&wq_mayday_lock);
+
+ /* rescuer will empty maydays list before exiting */
+ kthread_stop(rescuer->task);
+ kfree(rescuer);
+ }
+
/* sanity checks */
mutex_lock(&wq->mutex);
for_each_pwq(pwq, wq) {
@@ -4359,11 +4401,6 @@
list_del_rcu(&wq->list);
mutex_unlock(&wq_pool_mutex);
- workqueue_sysfs_unregister(wq);
-
- if (wq->rescuer)
- kthread_stop(wq->rescuer->task);
-
if (!(wq->flags & WQ_UNBOUND)) {
wq_unregister_lockdep(wq);
/*
@@ -4638,7 +4675,8 @@
pr_info(" pwq %d:", pool->id);
pr_cont_pool_info(pool);
- pr_cont(" active=%d/%d%s\n", pwq->nr_active, pwq->max_active,
+ pr_cont(" active=%d/%d refcnt=%d%s\n",
+ pwq->nr_active, pwq->max_active, pwq->refcnt,
!list_empty(&pwq->mayday_node) ? " MAYDAY" : "");
hash_for_each(pool->busy_hash, bkt, worker, hentry) {
@@ -5703,6 +5741,7 @@
{
unsigned long thresh = READ_ONCE(wq_watchdog_thresh) * HZ;
bool lockup_detected = false;
+ unsigned long now = jiffies;
struct worker_pool *pool;
int pi;
@@ -5717,6 +5756,12 @@
if (list_empty(&pool->worklist))
continue;
+ /*
+ * If a virtual machine is stopped by the host it can look to
+ * the watchdog like a stall.
+ */
+ kvm_check_and_clear_guest_paused();
+
/* get the latest of pool and touched timestamps */
pool_ts = READ_ONCE(pool->watchdog_ts);
touched = READ_ONCE(wq_watchdog_touched);
@@ -5735,12 +5780,12 @@
}
/* did we stall? */
- if (time_after(jiffies, ts + thresh)) {
+ if (time_after(now, ts + thresh)) {
lockup_detected = true;
pr_emerg("BUG: workqueue lockup - pool");
pr_cont_pool_info(pool);
pr_cont(" stuck for %us!\n",
- jiffies_to_msecs(jiffies - pool_ts) / 1000);
+ jiffies_to_msecs(now - pool_ts) / 1000);
}
}
@@ -5824,6 +5869,13 @@
return;
}
+ for_each_possible_cpu(cpu) {
+ if (WARN_ON(cpu_to_node(cpu) == NUMA_NO_NODE)) {
+ pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
+ return;
+ }
+ }
+
wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
BUG_ON(!wq_update_unbound_numa_attrs_buf);
@@ -5841,11 +5893,6 @@
for_each_possible_cpu(cpu) {
node = cpu_to_node(cpu);
- if (WARN_ON(node == NUMA_NO_NODE)) {
- pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
- /* happens iff arch is bonkers, let's just proceed */
- return;
- }
cpumask_set_cpu(cpu, tbl[node]);
}