21 files changed, 243 insertions, 102 deletions

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index befe570be5ba..c57bd10340ed 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -1459,7 +1459,8 @@ static int btf_modifier_resolve(struct btf_verifier_env *env,
 
                 /* "typedef void new_void", "const void"...etc */
                 if (!btf_type_is_void(next_type) &&
-                    !btf_type_is_fwd(next_type)) {
+                    !btf_type_is_fwd(next_type) &&
+                    !btf_type_is_func_proto(next_type)) {
                         btf_verifier_log_type(env, v->t, "Invalid type_id");
                         return -EINVAL;
                 }
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index ab612fe9862f..d17d05570a3f 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -572,7 +572,7 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk,
         bpf_compute_and_save_data_end(skb, &saved_data_end);
 
         ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], skb,
-                                 bpf_prog_run_save_cb);
+                                 __bpf_prog_run_save_cb);
         bpf_restore_data_end(skb, saved_data_end);
         __skb_pull(skb, offset);
         skb->sk = save_sk;
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 4b7c76765d9d..f9274114c88d 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -686,7 +686,7 @@ static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
         }
 
         if (htab_is_prealloc(htab)) {
-                pcpu_freelist_push(&htab->freelist, &l->fnode);
+                __pcpu_freelist_push(&htab->freelist, &l->fnode);
         } else {
                 atomic_dec(&htab->count);
                 l->htab = htab;
@@ -748,7 +748,7 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
                 } else {
                         struct pcpu_freelist_node *l;
 
-                        l = pcpu_freelist_pop(&htab->freelist);
+                        l = __pcpu_freelist_pop(&htab->freelist);
                         if (!l)
                                 return ERR_PTR(-E2BIG);
                         l_new = container_of(l, struct htab_elem, fnode);
diff --git a/kernel/bpf/percpu_freelist.c b/kernel/bpf/percpu_freelist.c
index 673fa6fe2d73..0c1b4ba9e90e 100644
--- a/kernel/bpf/percpu_freelist.c
+++ b/kernel/bpf/percpu_freelist.c
@@ -28,8 +28,8 @@ void pcpu_freelist_destroy(struct pcpu_freelist *s)
         free_percpu(s->freelist);
 }
 
-static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head,
-                                        struct pcpu_freelist_node *node)
+static inline void ___pcpu_freelist_push(struct pcpu_freelist_head *head,
+                                         struct pcpu_freelist_node *node)
 {
         raw_spin_lock(&head->lock);
         node->next = head->first;
@@ -37,12 +37,22 @@ static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head,
         raw_spin_unlock(&head->lock);
 }
 
-void pcpu_freelist_push(struct pcpu_freelist *s,
+void __pcpu_freelist_push(struct pcpu_freelist *s,
                         struct pcpu_freelist_node *node)
 {
         struct pcpu_freelist_head *head = this_cpu_ptr(s->freelist);
 
-        __pcpu_freelist_push(head, node);
+        ___pcpu_freelist_push(head, node);
+}
+
+void pcpu_freelist_push(struct pcpu_freelist *s,
+                        struct pcpu_freelist_node *node)
+{
+        unsigned long flags;
+
+        local_irq_save(flags);
+        __pcpu_freelist_push(s, node);
+        local_irq_restore(flags);
 }
 
 void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
@@ -63,7 +73,7 @@ void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
         for_each_possible_cpu(cpu) {
 again:
                 head = per_cpu_ptr(s->freelist, cpu);
-                __pcpu_freelist_push(head, buf);
+                ___pcpu_freelist_push(head, buf);
                 i++;
                 buf += elem_size;
                 if (i == nr_elems)
@@ -74,14 +84,12 @@ again:
         local_irq_restore(flags);
 }
 
-struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
+struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *s)
 {
         struct pcpu_freelist_head *head;
         struct pcpu_freelist_node *node;
-        unsigned long flags;
         int orig_cpu, cpu;
 
-        local_irq_save(flags);
         orig_cpu = cpu = raw_smp_processor_id();
         while (1) {
                 head = per_cpu_ptr(s->freelist, cpu);
@@ -89,16 +97,25 @@ struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
                 node = head->first;
                 if (node) {
                         head->first = node->next;
-                        raw_spin_unlock_irqrestore(&head->lock, flags);
+                        raw_spin_unlock(&head->lock);
                         return node;
                 }
                 raw_spin_unlock(&head->lock);
                 cpu = cpumask_next(cpu, cpu_possible_mask);
                 if (cpu >= nr_cpu_ids)
                         cpu = 0;
-                if (cpu == orig_cpu) {
-                        local_irq_restore(flags);
+                if (cpu == orig_cpu)
                         return NULL;
-                }
         }
 }
+
+struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
+{
+        struct pcpu_freelist_node *ret;
+        unsigned long flags;
+
+        local_irq_save(flags);
+        ret = __pcpu_freelist_pop(s);
+        local_irq_restore(flags);
+        return ret;
+}
diff --git a/kernel/bpf/percpu_freelist.h b/kernel/bpf/percpu_freelist.h
index 3049aae8ea1e..c3960118e617 100644
--- a/kernel/bpf/percpu_freelist.h
+++ b/kernel/bpf/percpu_freelist.h
@@ -22,8 +22,12 @@ struct pcpu_freelist_node {
         struct pcpu_freelist_node *next;
 };
 
+/* pcpu_freelist_* do spin_lock_irqsave. */
 void pcpu_freelist_push(struct pcpu_freelist *, struct pcpu_freelist_node *);
 struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *);
+/* __pcpu_freelist_* do spin_lock only. caller must disable irqs. */
+void __pcpu_freelist_push(struct pcpu_freelist *, struct pcpu_freelist_node *);
+struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *);
 void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
                             u32 nr_elems);
 int pcpu_freelist_init(struct pcpu_freelist *);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b155cd17c1bd..8577bb7f8be6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -713,8 +713,13 @@ static int map_lookup_elem(union bpf_attr *attr)
 
         if (bpf_map_is_dev_bound(map)) {
                 err = bpf_map_offload_lookup_elem(map, key, value);
-        } else if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
-                   map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
+                goto done;
+        }
+
+        preempt_disable();
+        this_cpu_inc(bpf_prog_active);
+        if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+            map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
                 err = bpf_percpu_hash_copy(map, key, value);
         } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
                 err = bpf_percpu_array_copy(map, key, value);
@@ -744,7 +749,10 @@ static int map_lookup_elem(union bpf_attr *attr)
                 }
                 rcu_read_unlock();
         }
+        this_cpu_dec(bpf_prog_active);
+        preempt_enable();
 
+done:
         if (err)
                 goto free_value;
 
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 91d5c38eb7e5..d1c6d152da89 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -376,9 +376,6 @@ void __weak arch_smt_update(void) { }
 
 #ifdef CONFIG_HOTPLUG_SMT
 enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED;
-EXPORT_SYMBOL_GPL(cpu_smt_control);
-
-static bool cpu_smt_available __read_mostly;
 
 void __init cpu_smt_disable(bool force)
 {
@@ -397,25 +394,11 @@ void __init cpu_smt_disable(bool force)
 
 /*
  * The decision whether SMT is supported can only be done after the full
- * CPU identification. Called from architecture code before non boot CPUs
- * are brought up.
- */
-void __init cpu_smt_check_topology_early(void)
-{
-        if (!topology_smt_supported())
-                cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
-}
-
-/*
- * If SMT was disabled by BIOS, detect it here, after the CPUs have been
- * brought online. This ensures the smt/l1tf sysfs entries are consistent
- * with reality. cpu_smt_available is set to true during the bringup of non
- * boot CPUs when a SMT sibling is detected. Note, this may overwrite
- * cpu_smt_control's previous setting.
+ * CPU identification. Called from architecture code.
  */
 void __init cpu_smt_check_topology(void)
 {
-        if (!cpu_smt_available)
+        if (!topology_smt_supported())
                 cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
 }
 
@@ -428,18 +411,10 @@ early_param("nosmt", smt_cmdline_disable);
 
 static inline bool cpu_smt_allowed(unsigned int cpu)
 {
-        if (topology_is_primary_thread(cpu))
+        if (cpu_smt_control == CPU_SMT_ENABLED)
                 return true;
 
-        /*
-         * If the CPU is not a 'primary' thread and the booted_once bit is
-         * set then the processor has SMT support. Store this information
-         * for the late check of SMT support in cpu_smt_check_topology().
-         */
-        if (per_cpu(cpuhp_state, cpu).booted_once)
-                cpu_smt_available = true;
-
-        if (cpu_smt_control == CPU_SMT_ENABLED)
+        if (topology_is_primary_thread(cpu))
                 return true;
 
         /*
@@ -2090,10 +2065,8 @@ static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
                  */
                 cpuhp_offline_cpu_device(cpu);
         }
-        if (!ret) {
+        if (!ret)
                 cpu_smt_control = ctrlval;
-                arch_smt_update();
-        }
         cpu_maps_update_done();
         return ret;
 }
@@ -2104,7 +2077,6 @@ static int cpuhp_smt_enable(void)
 
         cpu_maps_update_begin();
         cpu_smt_control = CPU_SMT_ENABLED;
-        arch_smt_update();
         for_each_present_cpu(cpu) {
                 /* Skip online CPUs and CPUs on offline nodes */
                 if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3cd13a30f732..e5ede6918050 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -436,18 +436,18 @@ int perf_proc_update_handler(struct ctl_table *table, int write,
                 void __user *buffer, size_t *lenp,
                 loff_t *ppos)
 {
-        int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
-
-        if (ret || !write)
-                return ret;
-
+        int ret;
+        int perf_cpu = sysctl_perf_cpu_time_max_percent;
         /*
          * If throttling is disabled don't allow the write:
          */
-        if (sysctl_perf_cpu_time_max_percent == 100 ||
-            sysctl_perf_cpu_time_max_percent == 0)
+        if (write && (perf_cpu == 100 || perf_cpu == 0))
                 return -EINVAL;
 
+        ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+        if (ret || !write)
+                return ret;
+
         max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
         perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
         update_perf_cpu_limits();
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 4a9937076331..309ef5a64af5 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -734,6 +734,9 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
         size = sizeof(struct ring_buffer);
         size += nr_pages * sizeof(void *);
 
+        if (order_base_2(size) >= MAX_ORDER)
+                goto fail;
+
         rb = kzalloc(size, GFP_KERNEL);
         if (!rb)
                 goto fail;
diff --git a/kernel/exit.c b/kernel/exit.c
index 3fb7be001964..2639a30a8aa5 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -558,12 +558,14 @@ static struct task_struct *find_alive_thread(struct task_struct *p)
         return NULL;
 }
 
-static struct task_struct *find_child_reaper(struct task_struct *father)
+static struct task_struct *find_child_reaper(struct task_struct *father,
+                                                struct list_head *dead)
         __releases(&tasklist_lock)
         __acquires(&tasklist_lock)
 {
         struct pid_namespace *pid_ns = task_active_pid_ns(father);
         struct task_struct *reaper = pid_ns->child_reaper;
+        struct task_struct *p, *n;
 
         if (likely(reaper != father))
                 return reaper;
@@ -579,6 +581,12 @@ static struct task_struct *find_child_reaper(struct task_struct *father)
                 panic("Attempted to kill init! exitcode=0x%08x\n",
                         father->signal->group_exit_code ?: father->exit_code);
         }
+
+        list_for_each_entry_safe(p, n, dead, ptrace_entry) {
+                list_del_init(&p->ptrace_entry);
+                release_task(p);
+        }
+
         zap_pid_ns_processes(pid_ns);
         write_lock_irq(&tasklist_lock);
 
@@ -668,7 +676,7 @@ static void forget_original_parent(struct task_struct *father,
                 exit_ptrace(father, dead);
 
         /* Can drop and reacquire tasklist_lock */
-        reaper = find_child_reaper(father);
+        reaper = find_child_reaper(father, dead);
         if (list_empty(&father->children))
                 return;
 
diff --git a/kernel/futex.c b/kernel/futex.c
index fdd312da0992..a0514e01c3eb 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2221,11 +2221,11 @@ static inline struct futex_hash_bucket *queue_lock(struct futex_q *q)
          * decrement the counter at queue_unlock() when some error has
          * occurred and we don't end up adding the task to the list.
          */
-        hb_waiters_inc(hb);
+        hb_waiters_inc(hb); /* implies smp_mb(); (A) */
 
         q->lock_ptr = &hb->lock;
 
-        spin_lock(&hb->lock); /* implies smp_mb(); (A) */
+        spin_lock(&hb->lock);
         return hb;
 }
 
@@ -2861,35 +2861,39 @@ retry_private:
          * and BUG when futex_unlock_pi() interleaves with this.
          *
          * Therefore acquire wait_lock while holding hb->lock, but drop the
-         * latter before calling rt_mutex_start_proxy_lock(). This still fully
-         * serializes against futex_unlock_pi() as that does the exact same
-         * lock handoff sequence.
+         * latter before calling __rt_mutex_start_proxy_lock(). This
+         * interleaves with futex_unlock_pi() -- which does a similar lock
+         * handoff -- such that the latter can observe the futex_q::pi_state
+         * before __rt_mutex_start_proxy_lock() is done.
          */
         raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
         spin_unlock(q.lock_ptr);
+        /*
+         * __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
+         * such that futex_unlock_pi() is guaranteed to observe the waiter when
+         * it sees the futex_q::pi_state.
+         */
         ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
         raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
 
         if (ret) {
                 if (ret == 1)
                         ret = 0;
-
-                spin_lock(q.lock_ptr);
-                goto no_block;
+                goto cleanup;
         }
 
-
         if (unlikely(to))
                 hrtimer_start_expires(&to->timer, HRTIMER_MODE_ABS);
 
         ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter);
 
+cleanup:
         spin_lock(q.lock_ptr);
         /*
-         * If we failed to acquire the lock (signal/timeout), we must
+         * If we failed to acquire the lock (deadlock/signal/timeout), we must
          * first acquire the hb->lock before removing the lock from the
-         * rt_mutex waitqueue, such that we can keep the hb and rt_mutex
-         * wait lists consistent.
+         * rt_mutex waitqueue, such that we can keep the hb and rt_mutex wait
+         * lists consistent.
          *
          * In particular; it is important that futex_unlock_pi() can not
          * observe this inconsistency.
@@ -3013,6 +3017,10 @@ retry:
                  * there is no point where we hold neither; and therefore
                  * wake_futex_pi() must observe a state consistent with what we
                  * observed.
+                 *
+                 * In particular; this forces __rt_mutex_start_proxy() to
+                 * complete such that we're guaranteed to observe the
+                 * rt_waiter. Also see the WARN in wake_futex_pi().
                  */
                 raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
                 spin_unlock(&hb->lock);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 581edcc63c26..978d63a8261c 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1726,12 +1726,33 @@ void rt_mutex_proxy_unlock(struct rt_mutex *lock,
         rt_mutex_set_owner(lock, NULL);
 }
 
+/**
+ * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task
+ * @lock:               the rt_mutex to take
+ * @waiter:             the pre-initialized rt_mutex_waiter
+ * @task:               the task to prepare
+ *
+ * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock
+ * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that.
+ *
+ * NOTE: does _NOT_ remove the @waiter on failure; must either call
+ * rt_mutex_wait_proxy_lock() or rt_mutex_cleanup_proxy_lock() after this.
+ *
+ * Returns:
+ *  0 - task blocked on lock
+ *  1 - acquired the lock for task, caller should wake it up
+ * <0 - error
+ *
+ * Special API call for PI-futex support.
+ */
 int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
                               struct rt_mutex_waiter *waiter,
                               struct task_struct *task)
 {
         int ret;
 
+        lockdep_assert_held(&lock->wait_lock);
+
         if (try_to_take_rt_mutex(lock, task, NULL))
                 return 1;
 
@@ -1749,9 +1770,6 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
                 ret = 0;
         }
 
-        if (unlikely(ret))
-                remove_waiter(lock, waiter);
-
         debug_rt_mutex_print_deadlock(waiter);
 
         return ret;
@@ -1763,12 +1781,18 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
  * @waiter:             the pre-initialized rt_mutex_waiter
  * @task:               the task to prepare
  *
+ * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock
+ * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that.
+ *
+ * NOTE: unlike __rt_mutex_start_proxy_lock this _DOES_ remove the @waiter
+ * on failure.
+ *
  * Returns:
  *  0 - task blocked on lock
  *  1 - acquired the lock for task, caller should wake it up
  * <0 - error
  *
- * Special API call for FUTEX_REQUEUE_PI support.
+ * Special API call for PI-futex support.
  */
 int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
                               struct rt_mutex_waiter *waiter,
@@ -1778,6 +1802,8 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 
         raw_spin_lock_irq(&lock->wait_lock);
         ret = __rt_mutex_start_proxy_lock(lock, waiter, task);
+        if (unlikely(ret))
+                remove_waiter(lock, waiter);
         raw_spin_unlock_irq(&lock->wait_lock);
 
         return ret;
@@ -1845,7 +1871,8 @@ int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
  * @lock:               the rt_mutex we were woken on
  * @waiter:             the pre-initialized rt_mutex_waiter
  *
- * Attempt to clean up after a failed rt_mutex_wait_proxy_lock().
+ * Attempt to clean up after a failed __rt_mutex_start_proxy_lock() or
+ * rt_mutex_wait_proxy_lock().
  *
  * Unless we acquired the lock; we're still enqueued on the wait-list and can
  * in fact still be granted ownership until we're removed. Therefore we can
diff --git a/kernel/relay.c b/kernel/relay.c
index 04f248644e06..9e0f52375487 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -428,6 +428,8 @@ static struct dentry *relay_create_buf_file(struct rchan *chan,
         dentry = chan->cb->create_buf_file(tmpname, chan->parent,
                                            S_IRUSR, buf,
                                            &chan->is_global);
+        if (IS_ERR(dentry))
+                dentry = NULL;
 
         kfree(tmpname);
 
@@ -461,7 +463,7 @@ static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
                 dentry = chan->cb->create_buf_file(NULL, NULL,
                                                    S_IRUSR, buf,
                                                    &chan->is_global);
-                if (WARN_ON(dentry))
+                if (IS_ERR_OR_NULL(dentry))
                         goto free_buf;
         }
 
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 50aa2aba69bd..310d0637fe4b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5980,6 +5980,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p
 
 #ifdef CONFIG_SCHED_SMT
 DEFINE_STATIC_KEY_FALSE(sched_smt_present);
+EXPORT_SYMBOL_GPL(sched_smt_present);
 
 static inline void set_idle_cores(int cpu, int val)
 {
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index fe24de3fbc93..c3484785b179 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -124,6 +124,7 @@
  * sampling of the aggregate task states would be.
  */
 
+#include "../workqueue_internal.h"
 #include <linux/sched/loadavg.h>
 #include <linux/seq_file.h>
 #include <linux/proc_fs.h>
@@ -480,9 +481,6 @@ static void psi_group_change(struct psi_group *group, int cpu,
                         groupc->tasks[t]++;
 
         write_seqcount_end(&groupc->seq);
-
-        if (!delayed_work_pending(&group->clock_work))
-                schedule_delayed_work(&group->clock_work, PSI_FREQ);
 }
 
 static struct psi_group *iterate_groups(struct task_struct *task, void **iter)
@@ -513,6 +511,7 @@ void psi_task_change(struct task_struct *task, int clear, int set)
 {
         int cpu = task_cpu(task);
         struct psi_group *group;
+        bool wake_clock = true;
         void *iter = NULL;
 
         if (!task->pid)
@@ -530,8 +529,22 @@ void psi_task_change(struct task_struct *task, int clear, int set)
         task->psi_flags &= ~clear;
         task->psi_flags |= set;
 
-        while ((group = iterate_groups(task, &iter)))
+        /*
+         * Periodic aggregation shuts off if there is a period of no
+         * task changes, so we wake it back up if necessary. However,
+         * don't do this if the task change is the aggregation worker
+         * itself going to sleep, or we'll ping-pong forever.
+         */
+        if (unlikely((clear & TSK_RUNNING) &&
+                     (task->flags & PF_WQ_WORKER) &&
+                     wq_worker_last_func(task) == psi_update_work))
+                wake_clock = false;
+
+        while ((group = iterate_groups(task, &iter))) {
                 psi_group_change(group, cpu, clear, set);
+                if (wake_clock && !delayed_work_pending(&group->clock_work))
+                        schedule_delayed_work(&group->clock_work, PSI_FREQ);
+        }
 }
 
 void psi_memstall_tick(struct task_struct *task, int cpu)
diff --git a/kernel/signal.c b/kernel/signal.c
index e1d7ad8e6ab1..99fa8ff06fd9 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -688,6 +688,48 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *in
 }
 EXPORT_SYMBOL_GPL(dequeue_signal);
 
+static int dequeue_synchronous_signal(kernel_siginfo_t *info)
+{
+        struct task_struct *tsk = current;
+        struct sigpending *pending = &tsk->pending;
+        struct sigqueue *q, *sync = NULL;
+
+        /*
+         * Might a synchronous signal be in the queue?
+         */
+        if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
+                return 0;
+
+        /*
+         * Return the first synchronous signal in the queue.
+         */
+        list_for_each_entry(q, &pending->list, list) {
+                /* Synchronous signals have a postive si_code */
+                if ((q->info.si_code > SI_USER) &&
+                    (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
+                        sync = q;
+                        goto next;
+                }
+        }
+        return 0;
+next:
+        /*
+         * Check if there is another siginfo for the same signal.
+         */
+        list_for_each_entry_continue(q, &pending->list, list) {
+                if (q->info.si_signo == sync->info.si_signo)
+                        goto still_pending;
+        }
+
+        sigdelset(&pending->signal, sync->info.si_signo);
+        recalc_sigpending();
+still_pending:
+        list_del_init(&sync->list);
+        copy_siginfo(info, &sync->info);
+        __sigqueue_free(sync);
+        return info->si_signo;
+}
+
 /*
  * Tell a process that it has a new active signal..
  *
@@ -1057,10 +1099,9 @@ static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struc
 
         result = TRACE_SIGNAL_DELIVERED;
         /*
-         * Skip useless siginfo allocation for SIGKILL SIGSTOP,
-         * and kernel threads.
+         * Skip useless siginfo allocation for SIGKILL and kernel threads.
          */
-        if (sig_kernel_only(sig) || (t->flags & PF_KTHREAD))
+        if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
                 goto out_set;
 
         /*
@@ -2394,6 +2435,11 @@ relock:
                 goto relock;
         }
 
+        /* Has this task already been marked for death? */
+        ksig->info.si_signo = signr = SIGKILL;
+        if (signal_group_exit(signal))
+                goto fatal;
+
         for (;;) {
                 struct k_sigaction *ka;
 
@@ -2407,7 +2453,15 @@ relock:
                         goto relock;
                 }
 
-                signr = dequeue_signal(current, &current->blocked, &ksig->info);
+                /*
+                 * Signals generated by the execution of an instruction
+                 * need to be delivered before any other pending signals
+                 * so that the instruction pointer in the signal stack
+                 * frame points to the faulting instruction.
+                 */
+                signr = dequeue_synchronous_signal(&ksig->info);
+                if (!signr)
+                        signr = dequeue_signal(current, &current->blocked, &ksig->info);
 
                 if (!signr)
                         break; /* will return 0 */
@@ -2489,6 +2543,7 @@ relock:
                         continue;
                 }
 
+        fatal:
                 spin_unlock_irq(&sighand->siglock);
 
                 /*
diff --git a/kernel/smp.c b/kernel/smp.c
index 163c451af42e..f4cf1b0bb3b8 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -584,8 +584,6 @@ void __init smp_init(void)
                 num_nodes, (num_nodes > 1 ? "s" : ""),
                 num_cpus,  (num_cpus  > 1 ? "s" : ""));
 
-        /* Final decision about SMT support */
-        cpu_smt_check_topology();
         /* Any cleanup work */
         smp_cpus_done(setup_max_cpus);
 }
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 8b068adb9da1..f1a86a0d881d 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1204,22 +1204,12 @@ static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *
 
 int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
 {
-        int err;
-
-        mutex_lock(&bpf_event_mutex);
-        err = __bpf_probe_register(btp, prog);
-        mutex_unlock(&bpf_event_mutex);
-        return err;
+        return __bpf_probe_register(btp, prog);
 }
 
 int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
 {
-        int err;
-
-        mutex_lock(&bpf_event_mutex);
-        err = tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog);
-        mutex_unlock(&bpf_event_mutex);
-        return err;
+        return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog);
 }
 
 int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index e335576b9411..9bde07c06362 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -5,7 +5,7 @@
  * Copyright (C) IBM Corporation, 2010-2012
  * Author:      Srikar Dronamraju <srikar@linux.vnet.ibm.com>
  */
-#define pr_fmt(fmt)     "trace_kprobe: " fmt
+#define pr_fmt(fmt)     "trace_uprobe: " fmt
 
 #include <linux/ctype.h>
 #include <linux/module.h>
@@ -160,6 +160,13 @@ fetch_store_string(unsigned long addr, void *dest, void *base)
         if (ret >= 0) {
                 if (ret == maxlen)
                         dst[ret - 1] = '\0';
+                else
+                        /*
+                         * Include the terminating null byte. In this case it
+                         * was copied by strncpy_from_user but not accounted
+                         * for in ret.
+                         */
+                        ret++;
                 *(u32 *)dest = make_data_loc(ret, (void *)dst - base);
         }
 
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 392be4b252f6..fc5d23d752a5 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -910,6 +910,26 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task)
 }
 
 /**
+ * wq_worker_last_func - retrieve worker's last work function
+ *
+ * Determine the last function a worker executed. This is called from
+ * the scheduler to get a worker's last known identity.
+ *
+ * CONTEXT:
+ * spin_lock_irq(rq->lock)
+ *
+ * Return:
+ * The last work function %current executed as a worker, NULL if it
+ * hasn't executed any work yet.
+ */
+work_func_t wq_worker_last_func(struct task_struct *task)
+{
+        struct worker *worker = kthread_data(task);
+
+        return worker->last_func;
+}
+
+/**
  * worker_set_flags - set worker flags and adjust nr_running accordingly
  * @worker: self
  * @flags: flags to set
@@ -2184,6 +2204,9 @@ __acquires(&pool->lock)
         if (unlikely(cpu_intensive))
                 worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
 
+        /* tag the worker for identification in schedule() */
+        worker->last_func = worker->current_func;
+
         /* we're done with it, release */
         hash_del(&worker->hentry);
         worker->current_work = NULL;
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index 66fbb5a9e633..cb68b03ca89a 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -53,6 +53,9 @@ struct worker {
 
         /* used only by rescuers to point to the target workqueue */
         struct workqueue_struct *rescue_wq;     /* I: the workqueue to rescue */
+
+        /* used by the scheduler to determine a worker's last known identity */
+        work_func_t             last_func;
 };
 
 /**
@@ -67,9 +70,10 @@ static inline struct worker *current_wq_worker(void)
 
 /*
  * Scheduler hooks for concurrency managed workqueue.  Only to be used from
- * sched/core.c and workqueue.c.
+ * sched/ and workqueue.c.
  */
 void wq_worker_waking_up(struct task_struct *task, int cpu);
 struct task_struct *wq_worker_sleeping(struct task_struct *task);
+work_func_t wq_worker_last_func(struct task_struct *task);
 
 #endif /* _KERNEL_WORKQUEUE_INTERNAL_H */