Merge branch 'perf/urgent' into perf/core, to pick up fixes

This also refreshes the -rc1 based branch to -rc5.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

43 files changed, 325 insertions, 462 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 4cb5441ad75f..d8520095ca03 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -16884,8 +16884,9 @@ static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old,
 		spi = i / BPF_REG_SIZE;
 
 		if (exact != NOT_EXACT &&
-		    old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
-		    cur->stack[spi].slot_type[i % BPF_REG_SIZE])
+		    (i >= cur->allocated_stack ||
+		     old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
+		     cur->stack[spi].slot_type[i % BPF_REG_SIZE]))
 			return false;
 
 		if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 40ec4abaf440..4bd9e50bcc8e 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -233,6 +233,13 @@ static cpumask_var_t	isolated_cpus;
 static struct list_head remote_children;
 
 /*
+ * A flag to force sched domain rebuild at the end of an operation while
+ * inhibiting it in the intermediate stages when set. Currently it is only
+ * set in hotplug code.
+ */
+static bool force_sd_rebuild;
+
+/*
  * Partition root states:
  *
  *   0 - member (not a partition root)
@@ -1475,7 +1482,7 @@ static void update_partition_sd_lb(struct cpuset *cs, int old_prs)
 			clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
 	}
 
-	if (rebuild_domains)
+	if (rebuild_domains && !force_sd_rebuild)
 		rebuild_sched_domains_locked();
 }
 
@@ -1833,7 +1840,7 @@ static void remote_partition_check(struct cpuset *cs, struct cpumask *newmask,
 			remote_partition_disable(child, tmp);
 			disable_cnt++;
 		}
-	if (disable_cnt)
+	if (disable_cnt && !force_sd_rebuild)
 		rebuild_sched_domains_locked();
 }
 
@@ -1991,6 +1998,8 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
 			part_error = PERR_CPUSEMPTY;
 			goto write_error;
 		}
+		/* Check newmask again, whether cpus are available for parent/cs */
+		nocpu |= tasks_nocpu_error(parent, cs, newmask);
 
 		/*
 		 * partcmd_update with newmask:
@@ -2440,7 +2449,8 @@ get_css:
 	}
 	rcu_read_unlock();
 
-	if (need_rebuild_sched_domains && !(flags & HIER_NO_SD_REBUILD))
+	if (need_rebuild_sched_domains && !(flags & HIER_NO_SD_REBUILD) &&
+	    !force_sd_rebuild)
 		rebuild_sched_domains_locked();
 }
 
@@ -2523,7 +2533,8 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 	 */
 	if (!*buf) {
 		cpumask_clear(trialcs->cpus_allowed);
-		cpumask_clear(trialcs->effective_xcpus);
+		if (cpumask_empty(trialcs->exclusive_cpus))
+			cpumask_clear(trialcs->effective_xcpus);
 	} else {
 		retval = cpulist_parse(buf, trialcs->cpus_allowed);
 		if (retval < 0)
@@ -3101,7 +3112,8 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
 	cs->flags = trialcs->flags;
 	spin_unlock_irq(&callback_lock);
 
-	if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
+	if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed &&
+	    !force_sd_rebuild)
 		rebuild_sched_domains_locked();
 
 	if (spread_flag_changed)
@@ -4498,11 +4510,9 @@ hotplug_update_tasks(struct cpuset *cs,
 		update_tasks_nodemask(cs);
 }
 
-static bool force_rebuild;
-
 void cpuset_force_rebuild(void)
 {
-	force_rebuild = true;
+	force_sd_rebuild = true;
 }
 
 /**
@@ -4650,15 +4660,9 @@ static void cpuset_handle_hotplug(void)
 		       !cpumask_empty(subpartitions_cpus);
 	mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
 
-	/*
-	 * In the rare case that hotplug removes all the cpus in
-	 * subpartitions_cpus, we assumed that cpus are updated.
-	 */
-	if (!cpus_updated && !cpumask_empty(subpartitions_cpus))
-		cpus_updated = true;
-
 	/* For v1, synchronize cpus_allowed to cpu_active_mask */
 	if (cpus_updated) {
+		cpuset_force_rebuild();
 		spin_lock_irq(&callback_lock);
 		if (!on_dfl)
 			cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
@@ -4714,8 +4718,8 @@ static void cpuset_handle_hotplug(void)
 	}
 
 	/* rebuild sched domains if cpus_allowed has changed */
-	if (cpus_updated || force_rebuild) {
-		force_rebuild = false;
+	if (force_sd_rebuild) {
+		force_sd_rebuild = false;
 		rebuild_sched_domains_cpuslocked();
 	}
 
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 1209ddaec026..b1fd2a3db91a 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2689,6 +2689,16 @@ int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
 	return ret;
 }
 
+/**
+ * Check if the core a CPU belongs to is online
+ */
+#if !defined(topology_is_core_online)
+static inline bool topology_is_core_online(unsigned int cpu)
+{
+	return true;
+}
+#endif
+
 int cpuhp_smt_enable(void)
 {
 	int cpu, ret = 0;
@@ -2699,7 +2709,7 @@ int cpuhp_smt_enable(void)
 		/* Skip online CPUs and CPUs on offline nodes */
 		if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
 			continue;
-		if (!cpu_smt_thread_allowed(cpu))
+		if (!cpu_smt_thread_allowed(cpu) || !topology_is_core_online(cpu))
 			continue;
 		ret = _cpu_up(cpu, 0, CPUHP_ONLINE);
 		if (ret)
diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
index d3b4cd12bdd1..64d44a52c011 100644
--- a/kernel/crash_reserve.c
+++ b/kernel/crash_reserve.c
@@ -423,7 +423,8 @@ retry:
 		if (high && search_end == CRASH_ADDR_HIGH_MAX) {
 			search_end = CRASH_ADDR_LOW_MAX;
 			search_base = 0;
-			goto retry;
+			if (search_end != CRASH_ADDR_HIGH_MAX)
+				goto retry;
 		}
 		pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
 			crash_size);
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index a6e3792b15f8..d570535342cb 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -416,8 +416,11 @@ static unsigned long long phys_addr(struct dma_debug_entry *entry)
  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
  * entries into the tree.
+ *
+ * Use __GFP_NOWARN because the printk from an OOM, to netconsole, could end
+ * up right back in the DMA debugging code, leading to a deadlock.
  */
-static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC);
+static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC | __GFP_NOWARN);
 static DEFINE_SPINLOCK(radix_lock);
 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c6a720f41225..4acec97e5448 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1286,8 +1286,9 @@ static void put_ctx(struct perf_event_context *ctx)
  *	  perf_event_context::mutex
  *	    perf_event::child_mutex;
  *	      perf_event_context::lock
- *	    perf_event::mmap_mutex
  *	    mmap_lock
+ *	      perf_event::mmap_mutex
+ *	        perf_buffer::aux_mutex
  *	      perf_addr_filters_head::lock
  *
  *    cpu_hotplug_lock
@@ -6458,12 +6459,11 @@ static void perf_mmap_close(struct vm_area_struct *vma)
 		event->pmu->event_unmapped(event, vma->vm_mm);
 
 	/*
-	 * rb->aux_mmap_count will always drop before rb->mmap_count and
-	 * event->mmap_count, so it is ok to use event->mmap_mutex to
-	 * serialize with perf_mmap here.
+	 * The AUX buffer is strictly a sub-buffer, serialize using aux_mutex
+	 * to avoid complications.
 	 */
 	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
-	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
+	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &rb->aux_mutex)) {
 		/*
 		 * Stop all AUX events that are writing to this buffer,
 		 * so that we can free its AUX pages and corresponding PMU
@@ -6480,7 +6480,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)
 		rb_free_aux(rb);
 		WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
 
-		mutex_unlock(&event->mmap_mutex);
+		mutex_unlock(&rb->aux_mutex);
 	}
 
 	if (atomic_dec_and_test(&rb->mmap_count))
@@ -6568,6 +6568,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 	struct perf_event *event = file->private_data;
 	unsigned long user_locked, user_lock_limit;
 	struct user_struct *user = current_user();
+	struct mutex *aux_mutex = NULL;
 	struct perf_buffer *rb = NULL;
 	unsigned long locked, lock_limit;
 	unsigned long vma_size;
@@ -6616,6 +6617,9 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 		if (!rb)
 			goto aux_unlock;
 
+		aux_mutex = &rb->aux_mutex;
+		mutex_lock(aux_mutex);
+
 		aux_offset = READ_ONCE(rb->user_page->aux_offset);
 		aux_size = READ_ONCE(rb->user_page->aux_size);
 
@@ -6766,6 +6770,8 @@ unlock:
 		atomic_dec(&rb->mmap_count);
 	}
 aux_unlock:
+	if (aux_mutex)
+		mutex_unlock(aux_mutex);
 	mutex_unlock(&event->mmap_mutex);
 
 	/*
@@ -9796,7 +9802,8 @@ static int __perf_event_overflow(struct perf_event *event,
 
 	ret = __perf_event_account_interrupt(event, throttle);
 
-	if (event->prog && !bpf_overflow_handler(event, data, regs))
+	if (event->prog && event->prog->type == BPF_PROG_TYPE_PERF_EVENT &&
+	    !bpf_overflow_handler(event, data, regs))
 		return ret;
 
 	/*
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index 451514442a1b..e072d995d670 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -40,6 +40,7 @@ struct perf_buffer {
 	struct user_struct		*mmap_user;
 
 	/* AUX area */
+	struct mutex			aux_mutex;
 	long				aux_head;
 	unsigned int			aux_nest;
 	long				aux_wakeup;	/* last aux_watermark boundary crossed by aux_head */
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 8cadf97bc290..4f46f688d0d4 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -337,6 +337,8 @@ ring_buffer_init(struct perf_buffer *rb, long watermark, int flags)
 	 */
 	if (!rb->nr_pages)
 		rb->paused = 1;
+
+	mutex_init(&rb->aux_mutex);
 }
 
 void perf_aux_output_flag(struct perf_output_handle *handle, u64 flags)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 30348f13d4a7..cac45ea4c284 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1470,7 +1470,7 @@ static struct xol_area *__create_xol_area(unsigned long vaddr)
 	struct xol_area *area;
 	void *insns;
 
-	area = kmalloc(sizeof(*area), GFP_KERNEL);
+	area = kzalloc(sizeof(*area), GFP_KERNEL);
 	if (unlikely(!area))
 		goto out;
 
@@ -1480,7 +1480,6 @@ static struct xol_area *__create_xol_area(unsigned long vaddr)
 		goto free_area;
 
 	area->xol_mapping.name = "[uprobes]";
-	area->xol_mapping.fault = NULL;
 	area->xol_mapping.pages = area->pages;
 	area->pages[0] = alloc_page(GFP_HIGHUSER);
 	if (!area->pages[0])
diff --git a/kernel/fork.c b/kernel/fork.c
index cc760491f201..18bdc87209d0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2053,11 +2053,24 @@ static int __pidfd_prepare(struct pid *pid, unsigned int flags, struct file **re
  */
 int pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret)
 {
-	bool thread = flags & PIDFD_THREAD;
-
-	if (!pid || !pid_has_task(pid, thread ? PIDTYPE_PID : PIDTYPE_TGID))
+	if (!pid)
 		return -EINVAL;
 
+	scoped_guard(rcu) {
+		struct task_struct *tsk;
+
+		if (flags & PIDFD_THREAD)
+			tsk = pid_task(pid, PIDTYPE_PID);
+		else
+			tsk = pid_task(pid, PIDTYPE_TGID);
+		if (!tsk)
+			return -EINVAL;
+
+		/* Don't create pidfds for kernel threads for now. */
+		if (tsk->flags & PF_KTHREAD)
+			return -EINVAL;
+	}
+
 	return __pidfd_prepare(pid, flags, ret);
 }
 
@@ -2403,6 +2416,12 @@ __latent_entropy struct task_struct *copy_process(
 	if (clone_flags & CLONE_PIDFD) {
 		int flags = (clone_flags & CLONE_THREAD) ? PIDFD_THREAD : 0;
 
+		/* Don't create pidfds for kernel threads for now. */
+		if (args->kthread) {
+			retval = -EINVAL;
+			goto bad_fork_free_pid;
+		}
+
 		/* Note that no task has been attached to @pid yet. */
 		retval = __pidfd_prepare(pid, flags, &pidfile);
 		if (retval < 0)
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 07e99c936ba5..1dee88ba0ae4 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -530,6 +530,7 @@ static int alloc_descs(unsigned int start, unsigned int cnt, int node,
 				flags = IRQD_AFFINITY_MANAGED |
 					IRQD_MANAGED_SHUTDOWN;
 			}
+			flags |= IRQD_AFFINITY_SET;
 			mask = &affinity->mask;
 			node = cpu_to_node(cpumask_first(mask));
 			affinity++;
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 4ad5ed8adf96..6dc76b590703 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -236,7 +236,7 @@ void static_key_disable_cpuslocked(struct static_key *key)
 	}
 
 	jump_label_lock();
-	if (atomic_cmpxchg(&key->enabled, 1, 0))
+	if (atomic_cmpxchg(&key->enabled, 1, 0) == 1)
 		jump_label_update(key);
 	jump_label_unlock();
 }
@@ -289,7 +289,7 @@ static void __static_key_slow_dec_cpuslocked(struct static_key *key)
 		return;
 
 	guard(mutex)(&jump_label_mutex);
-	if (atomic_cmpxchg(&key->enabled, 1, 0))
+	if (atomic_cmpxchg(&key->enabled, 1, 0) == 1)
 		jump_label_update(key);
 	else
 		WARN_ON_ONCE(!static_key_slow_try_dec(key));
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fb2c77368d18..a9a0ca605d4a 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -160,38 +160,6 @@ unsigned long kallsyms_sym_address(int idx)
 	return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
 }
 
-static void cleanup_symbol_name(char *s)
-{
-	char *res;
-
-	if (!IS_ENABLED(CONFIG_LTO_CLANG))
-		return;
-
-	/*
-	 * LLVM appends various suffixes for local functions and variables that
-	 * must be promoted to global scope as part of LTO.  This can break
-	 * hooking of static functions with kprobes. '.' is not a valid
-	 * character in an identifier in C. Suffixes only in LLVM LTO observed:
-	 * - foo.llvm.[0-9a-f]+
-	 */
-	res = strstr(s, ".llvm.");
-	if (res)
-		*res = '\0';
-
-	return;
-}
-
-static int compare_symbol_name(const char *name, char *namebuf)
-{
-	/* The kallsyms_seqs_of_names is sorted based on names after
-	 * cleanup_symbol_name() (see scripts/kallsyms.c) if clang lto is enabled.
-	 * To ensure correct bisection in kallsyms_lookup_names(), do
-	 * cleanup_symbol_name(namebuf) before comparing name and namebuf.
-	 */
-	cleanup_symbol_name(namebuf);
-	return strcmp(name, namebuf);
-}
-
 static unsigned int get_symbol_seq(int index)
 {
 	unsigned int i, seq = 0;
@@ -219,7 +187,7 @@ static int kallsyms_lookup_names(const char *name,
 		seq = get_symbol_seq(mid);
 		off = get_symbol_offset(seq);
 		kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
-		ret = compare_symbol_name(name, namebuf);
+		ret = strcmp(name, namebuf);
 		if (ret > 0)
 			low = mid + 1;
 		else if (ret < 0)
@@ -236,7 +204,7 @@ static int kallsyms_lookup_names(const char *name,
 		seq = get_symbol_seq(low - 1);
 		off = get_symbol_offset(seq);
 		kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
-		if (compare_symbol_name(name, namebuf))
+		if (strcmp(name, namebuf))
 			break;
 		low--;
 	}
@@ -248,7 +216,7 @@ static int kallsyms_lookup_names(const char *name,
 			seq = get_symbol_seq(high + 1);
 			off = get_symbol_offset(seq);
 			kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
-			if (compare_symbol_name(name, namebuf))
+			if (strcmp(name, namebuf))
 				break;
 			high++;
 		}
@@ -407,8 +375,7 @@ static int kallsyms_lookup_buildid(unsigned long addr,
 		if (modbuildid)
 			*modbuildid = NULL;
 
-		ret = strlen(namebuf);
-		goto found;
+		return strlen(namebuf);
 	}
 
 	/* See if it's in a module or a BPF JITed image. */
@@ -422,8 +389,6 @@ static int kallsyms_lookup_buildid(unsigned long addr,
 		ret = ftrace_mod_address_lookup(addr, symbolsize,
 						offset, modname, namebuf);
 
-found:
-	cleanup_symbol_name(namebuf);
 	return ret;
 }
 
@@ -450,8 +415,6 @@ const char *kallsyms_lookup(unsigned long addr,
 
 int lookup_symbol_name(unsigned long addr, char *symname)
 {
-	int res;
-
 	symname[0] = '\0';
 	symname[KSYM_NAME_LEN - 1] = '\0';
 
@@ -462,16 +425,10 @@ int lookup_symbol_name(unsigned long addr, char *symname)
 		/* Grab name */
 		kallsyms_expand_symbol(get_symbol_offset(pos),
 				       symname, KSYM_NAME_LEN);
-		goto found;
+		return 0;
 	}
 	/* See if it's in a module. */
-	res = lookup_module_symbol_name(addr, symname);
-	if (res)
-		return res;
-
-found:
-	cleanup_symbol_name(symname);
-	return 0;
+	return lookup_module_symbol_name(addr, symname);
 }
 
 /* Look up a kernel symbol and return it in a text buffer. */
diff --git a/kernel/kallsyms_selftest.c b/kernel/kallsyms_selftest.c
index 2f84896a7bcb..873f7c445488 100644
--- a/kernel/kallsyms_selftest.c
+++ b/kernel/kallsyms_selftest.c
@@ -187,31 +187,11 @@ static void test_perf_kallsyms_lookup_name(void)
 		stat.min, stat.max, div_u64(stat.sum, stat.real_cnt));
 }
 
-static bool match_cleanup_name(const char *s, const char *name)
-{
-	char *p;
-	int len;
-
-	if (!IS_ENABLED(CONFIG_LTO_CLANG))
-		return false;
-
-	p = strstr(s, ".llvm.");
-	if (!p)
-		return false;
-
-	len = strlen(name);
-	if (p - s != len)
-		return false;
-
-	return !strncmp(s, name, len);
-}
-
 static int find_symbol(void *data, const char *name, unsigned long addr)
 {
 	struct test_stat *stat = (struct test_stat *)data;
 
-	if (strcmp(name, stat->name) == 0 ||
-	    (!stat->perf && match_cleanup_name(name, stat->name))) {
+	if (!strcmp(name, stat->name)) {
 		stat->real_cnt++;
 		stat->addr = addr;
 
diff --git a/kernel/kcov.c b/kernel/kcov.c
index f0a69d402066..274b6b7c718d 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -161,6 +161,15 @@ static void kcov_remote_area_put(struct kcov_remote_area *area,
 	kmsan_unpoison_memory(&area->list, sizeof(area->list));
 }
 
+/*
+ * Unlike in_serving_softirq(), this function returns false when called during
+ * a hardirq or an NMI that happened in the softirq context.
+ */
+static inline bool in_softirq_really(void)
+{
+	return in_serving_softirq() && !in_hardirq() && !in_nmi();
+}
+
 static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
 {
 	unsigned int mode;
@@ -170,7 +179,7 @@ static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_stru
 	 * so we ignore code executed in interrupts, unless we are in a remote
 	 * coverage collection section in a softirq.
 	 */
-	if (!in_task() && !(in_serving_softirq() && t->kcov_softirq))
+	if (!in_task() && !(in_softirq_really() && t->kcov_softirq))
 		return false;
 	mode = READ_ONCE(t->kcov_mode);
 	/*
@@ -849,7 +858,7 @@ void kcov_remote_start(u64 handle)
 
 	if (WARN_ON(!kcov_check_handle(handle, true, true, true)))
 		return;
-	if (!in_task() && !in_serving_softirq())
+	if (!in_task() && !in_softirq_really())
 		return;
 
 	local_lock_irqsave(&kcov_percpu_data.lock, flags);
@@ -991,7 +1000,7 @@ void kcov_remote_stop(void)
 	int sequence;
 	unsigned long flags;
 
-	if (!in_task() && !in_serving_softirq())
+	if (!in_task() && !in_softirq_really())
 		return;
 
 	local_lock_irqsave(&kcov_percpu_data.lock, flags);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e85de37d9e1e..da59c68df841 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1557,8 +1557,8 @@ static bool is_cfi_preamble_symbol(unsigned long addr)
 	if (lookup_symbol_name(addr, symbuf))
 		return false;
 
-	return str_has_prefix("__cfi_", symbuf) ||
-		str_has_prefix("__pfx_", symbuf);
+	return str_has_prefix(symbuf, "__cfi_") ||
+		str_has_prefix(symbuf, "__pfx_");
 }
 
 static int check_kprobe_address_safe(struct kprobe *p,
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index 07fb5987b42b..1bab21b4718f 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -92,7 +92,14 @@ static ssize_t profiling_store(struct kobject *kobj,
 				   const char *buf, size_t count)
 {
 	int ret;
+	static DEFINE_MUTEX(lock);
 
+	/*
+	 * We need serialization, for profile_setup() initializes prof_on
+	 * value and profile_init() must not reallocate prof_buffer after
+	 * once allocated.
+	 */
+	guard(mutex)(&lock);
 	if (prof_on)
 		return -EEXIST;
 	/*
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 58c88220a478..0349f957e672 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -5936,6 +5936,9 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip)
 	if (DEBUG_LOCKS_WARN_ON(!depth))
 		return;
 
+	if (unlikely(lock->key == &__lockdep_no_track__))
+		return;
+
 	hlock = find_held_lock(curr, lock, depth, &i);
 	if (!hlock) {
 		print_lock_contention_bug(curr, lock, ip);
@@ -5978,6 +5981,9 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip)
 	if (DEBUG_LOCKS_WARN_ON(!depth))
 		return;
 
+	if (unlikely(lock->key == &__lockdep_no_track__))
+		return;
+
 	hlock = find_held_lock(curr, lock, depth, &i);
 	if (!hlock) {
 		print_lock_contention_bug(curr, lock, _RET_IP_);
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index f5a36e67b593..ac2e22502741 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -357,7 +357,7 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
 static void pv_kick_node(struct qspinlock *lock, struct mcs_spinlock *node)
 {
 	struct pv_node *pn = (struct pv_node *)node;
-	enum vcpu_state old = vcpu_halted;
+	u8 old = vcpu_halted;
 	/*
 	 * If the vCPU is indeed halted, advance its state to match that of
 	 * pv_wait_node(). If OTOH this fails, the vCPU was running and will
diff --git a/kernel/module/main.c b/kernel/module/main.c
index d9592195c5bb..71396e297499 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -3104,7 +3104,7 @@ static bool idempotent(struct idempotent *u, const void *cookie)
 	struct idempotent *existing;
 	bool first;
 
-	u->ret = 0;
+	u->ret = -EINTR;
 	u->cookie = cookie;
 	init_completion(&u->complete);
 
@@ -3140,7 +3140,7 @@ static int idempotent_complete(struct idempotent *u, int ret)
 	hlist_for_each_entry_safe(pos, next, head, entry) {
 		if (pos->cookie != cookie)
 			continue;
-		hlist_del(&pos->entry);
+		hlist_del_init(&pos->entry);
 		pos->ret = ret;
 		complete(&pos->complete);
 	}
@@ -3148,6 +3148,28 @@ static int idempotent_complete(struct idempotent *u, int ret)
 	return ret;
 }
 
+/*
+ * Wait for the idempotent worker.
+ *
+ * If we get interrupted, we need to remove ourselves from the
+ * the idempotent list, and the completion may still come in.
+ *
+ * The 'idem_lock' protects against the race, and 'idem.ret' was
+ * initialized to -EINTR and is thus always the right return
+ * value even if the idempotent work then completes between
+ * the wait_for_completion and the cleanup.
+ */
+static int idempotent_wait_for_completion(struct idempotent *u)
+{
+	if (wait_for_completion_interruptible(&u->complete)) {
+		spin_lock(&idem_lock);
+		if (!hlist_unhashed(&u->entry))
+			hlist_del(&u->entry);
+		spin_unlock(&idem_lock);
+	}
+	return u->ret;
+}
+
 static int init_module_from_file(struct file *f, const char __user * uargs, int flags)
 {
 	struct load_info info = { };
@@ -3183,15 +3205,16 @@ static int idempotent_init_module(struct file *f, const char __user * uargs, int
 	if (!f || !(f->f_mode & FMODE_READ))
 		return -EBADF;
 
-	/* See if somebody else is doing the operation? */
-	if (idempotent(&idem, file_inode(f))) {
-		wait_for_completion(&idem.complete);
-		return idem.ret;
+	/* Are we the winners of the race and get to do this? */
+	if (!idempotent(&idem, file_inode(f))) {
+		int ret = init_module_from_file(f, uargs, flags);
+		return idempotent_complete(&idem, ret);
 	}
 
-	/* Otherwise, we'll do it and complete others */
-	return idempotent_complete(&idem,
-		init_module_from_file(f, uargs, flags));
+	/*
+	 * Somebody else won the race and is loading the module.
+	 */
+	return idempotent_wait_for_completion(&idem);
 }
 
 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
diff --git a/kernel/padata.c b/kernel/padata.c
index 53f4bc912712..0fa6c2895460 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -517,6 +517,13 @@ void __init padata_do_multithreaded(struct padata_mt_job *job)
 	ps.chunk_size = max(ps.chunk_size, job->min_chunk);
 	ps.chunk_size = roundup(ps.chunk_size, job->align);
 
+	/*
+	 * chunk_size can be 0 if the caller sets min_chunk to 0. So force it
+	 * to at least 1 to prevent divide-by-0 panic in padata_mt_helper().`
+	 */
+	if (!ps.chunk_size)
+		ps.chunk_size = 1U;
+
 	list_for_each_entry(pw, &works, pw_list)
 		if (job->numa_aware) {
 			int old_node = atomic_read(&last_used_nid);
diff --git a/kernel/panic.c b/kernel/panic.c
index f861bedc1925..2a0449144f82 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -64,6 +64,8 @@ unsigned long panic_on_taint;
 bool panic_on_taint_nousertaint = false;
 static unsigned int warn_limit __read_mostly;
 
+bool panic_triggering_all_cpu_backtrace;
+
 int panic_timeout = CONFIG_PANIC_TIMEOUT;
 EXPORT_SYMBOL_GPL(panic_timeout);
 
@@ -253,8 +255,12 @@ void check_panic_on_warn(const char *origin)
  */
 static void panic_other_cpus_shutdown(bool crash_kexec)
 {
-	if (panic_print & PANIC_PRINT_ALL_CPU_BT)
+	if (panic_print & PANIC_PRINT_ALL_CPU_BT) {
+		/* Temporary allow non-panic CPUs to write their backtraces. */
+		panic_triggering_all_cpu_backtrace = true;
 		trigger_all_cpu_backtrace();
+		panic_triggering_all_cpu_backtrace = false;
+	}
 
 	/*
 	 * Note that smp_send_stop() is the usual SMP shutdown function,
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 054c0e7784fd..c22b07049c38 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2316,7 +2316,7 @@ asmlinkage int vprintk_emit(int facility, int level,
 	 * non-panic CPUs are generating any messages, they will be
 	 * silently dropped.
 	 */
-	if (other_cpu_in_panic())
+	if (other_cpu_in_panic() && !panic_triggering_all_cpu_backtrace)
 		return 0;
 
 	if (level == LOGLEVEL_SCHED) {
diff --git a/kernel/profile.c b/kernel/profile.c
index 2b775cc5c28f..1fcf1adcf4eb 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -47,30 +47,14 @@ static unsigned short int prof_shift;
 int prof_on __read_mostly;
 EXPORT_SYMBOL_GPL(prof_on);
 
-static cpumask_var_t prof_cpu_mask;
-#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
-static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
-static DEFINE_PER_CPU(int, cpu_profile_flip);
-static DEFINE_MUTEX(profile_flip_mutex);
-#endif /* CONFIG_SMP */
-
 int profile_setup(char *str)
 {
 	static const char schedstr[] = "schedule";
-	static const char sleepstr[] = "sleep";
 	static const char kvmstr[] = "kvm";
 	const char *select = NULL;
 	int par;
 
-	if (!strncmp(str, sleepstr, strlen(sleepstr))) {
-#ifdef CONFIG_SCHEDSTATS
-		force_schedstat_enabled();
-		prof_on = SLEEP_PROFILING;
-		select = sleepstr;
-#else
-		pr_warn("kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
-#endif /* CONFIG_SCHEDSTATS */
-	} else if (!strncmp(str, schedstr, strlen(schedstr))) {
+	if (!strncmp(str, schedstr, strlen(schedstr))) {
 		prof_on = SCHED_PROFILING;
 		select = schedstr;
 	} else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
@@ -114,11 +98,6 @@ int __ref profile_init(void)
 
 	buffer_bytes = prof_len*sizeof(atomic_t);
 
-	if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
-		return -ENOMEM;
-
-	cpumask_copy(prof_cpu_mask, cpu_possible_mask);
-
 	prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN);
 	if (prof_buffer)
 		return 0;
@@ -132,195 +111,16 @@ int __ref profile_init(void)
 	if (prof_buffer)
 		return 0;
 
-	free_cpumask_var(prof_cpu_mask);
 	return -ENOMEM;
 }
 
-#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
-/*
- * Each cpu has a pair of open-addressed hashtables for pending
- * profile hits. read_profile() IPI's all cpus to request them
- * to flip buffers and flushes their contents to prof_buffer itself.
- * Flip requests are serialized by the profile_flip_mutex. The sole
- * use of having a second hashtable is for avoiding cacheline
- * contention that would otherwise happen during flushes of pending
- * profile hits required for the accuracy of reported profile hits
- * and so resurrect the interrupt livelock issue.
- *
- * The open-addressed hashtables are indexed by profile buffer slot
- * and hold the number of pending hits to that profile buffer slot on
- * a cpu in an entry. When the hashtable overflows, all pending hits
- * are accounted to their corresponding profile buffer slots with
- * atomic_add() and the hashtable emptied. As numerous pending hits
- * may be accounted to a profile buffer slot in a hashtable entry,
- * this amortizes a number of atomic profile buffer increments likely
- * to be far larger than the number of entries in the hashtable,
- * particularly given that the number of distinct profile buffer
- * positions to which hits are accounted during short intervals (e.g.
- * several seconds) is usually very small. Exclusion from buffer
- * flipping is provided by interrupt disablement (note that for
- * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
- * process context).
- * The hash function is meant to be lightweight as opposed to strong,
- * and was vaguely inspired by ppc64 firmware-supported inverted
- * pagetable hash functions, but uses a full hashtable full of finite
- * collision chains, not just pairs of them.
- *
- * -- nyc
- */
-static void __profile_flip_buffers(void *unused)
-{
-	int cpu = smp_processor_id();
-
-	per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
-}
-
-static void profile_flip_buffers(void)
-{
-	int i, j, cpu;
-
-	mutex_lock(&profile_flip_mutex);
-	j = per_cpu(cpu_profile_flip, get_cpu());
-	put_cpu();
-	on_each_cpu(__profile_flip_buffers, NULL, 1);
-	for_each_online_cpu(cpu) {
-		struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
-		for (i = 0; i < NR_PROFILE_HIT; ++i) {
-			if (!hits[i].hits) {
-				if (hits[i].pc)
-					hits[i].pc = 0;
-				continue;
-			}
-			atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
-			hits[i].hits = hits[i].pc = 0;
-		}
-	}
-	mutex_unlock(&profile_flip_mutex);
-}
-
-static void profile_discard_flip_buffers(void)
-{
-	int i, cpu;
-
-	mutex_lock(&profile_flip_mutex);
-	i = per_cpu(cpu_profile_flip, get_cpu());
-	put_cpu();
-	on_each_cpu(__profile_flip_buffers, NULL, 1);
-	for_each_online_cpu(cpu) {
-		struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
-		memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
-	}
-	mutex_unlock(&profile_flip_mutex);
-}
-
-static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
-{
-	unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
-	int i, j, cpu;
-	struct profile_hit *hits;
-
-	pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
-	i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
-	secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
-	cpu = get_cpu();
-	hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
-	if (!hits) {
-		put_cpu();
-		return;
-	}
-	/*
-	 * We buffer the global profiler buffer into a per-CPU
-	 * queue and thus reduce the number of global (and possibly
-	 * NUMA-alien) accesses. The write-queue is self-coalescing:
-	 */
-	local_irq_save(flags);
-	do {
-		for (j = 0; j < PROFILE_GRPSZ; ++j) {
-			if (hits[i + j].pc == pc) {
-				hits[i + j].hits += nr_hits;
-				goto out;
-			} else if (!hits[i + j].hits) {
-				hits[i + j].pc = pc;
-				hits[i + j].hits = nr_hits;
-				goto out;
-			}
-		}
-		i = (i + secondary) & (NR_PROFILE_HIT - 1);
-	} while (i != primary);
-
-	/*
-	 * Add the current hit(s) and flush the write-queue out
-	 * to the global buffer:
-	 */
-	atomic_add(nr_hits, &prof_buffer[pc]);
-	for (i = 0; i < NR_PROFILE_HIT; ++i) {
-		atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
-		hits[i].pc = hits[i].hits = 0;
-	}
-out:
-	local_irq_restore(flags);
-	put_cpu();
-}
-
-static int profile_dead_cpu(unsigned int cpu)
-{
-	struct page *page;
-	int i;
-
-	if (cpumask_available(prof_cpu_mask))
-		cpumask_clear_cpu(cpu, prof_cpu_mask);
-
-	for (i = 0; i < 2; i++) {
-		if (per_cpu(cpu_profile_hits, cpu)[i]) {
-			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[i]);
-			per_cpu(cpu_profile_hits, cpu)[i] = NULL;
-			__free_page(page);
-		}
-	}
-	return 0;
-}
-
-static int profile_prepare_cpu(unsigned int cpu)
-{
-	int i, node = cpu_to_mem(cpu);
-	struct page *page;
-
-	per_cpu(cpu_profile_flip, cpu) = 0;
-
-	for (i = 0; i < 2; i++) {
-		if (per_cpu(cpu_profile_hits, cpu)[i])
-			continue;
-
-		page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
-		if (!page) {
-			profile_dead_cpu(cpu);
-			return -ENOMEM;
-		}
-		per_cpu(cpu_profile_hits, cpu)[i] = page_address(page);
-
-	}
-	return 0;
-}
-
-static int profile_online_cpu(unsigned int cpu)
-{
-	if (cpumask_available(prof_cpu_mask))
-		cpumask_set_cpu(cpu, prof_cpu_mask);
-
-	return 0;
-}
-
-#else /* !CONFIG_SMP */
-#define profile_flip_buffers()		do { } while (0)
-#define profile_discard_flip_buffers()	do { } while (0)
-
 static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
 {
 	unsigned long pc;
 	pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
-	atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
+	if (pc < prof_len)
+		atomic_add(nr_hits, &prof_buffer[pc]);
 }
-#endif /* !CONFIG_SMP */
 
 void profile_hits(int type, void *__pc, unsigned int nr_hits)
 {
@@ -334,8 +134,8 @@ void profile_tick(int type)
 {
 	struct pt_regs *regs = get_irq_regs();
 
-	if (!user_mode(regs) && cpumask_available(prof_cpu_mask) &&
-	    cpumask_test_cpu(smp_processor_id(), prof_cpu_mask))
+	/* This is the old kernel-only legacy profiling */
+	if (!user_mode(regs))
 		profile_hit(type, (void *)profile_pc(regs));
 }
 
@@ -358,7 +158,6 @@ read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 	char *pnt;
 	unsigned long sample_step = 1UL << prof_shift;
 
-	profile_flip_buffers();
 	if (p >= (prof_len+1)*sizeof(unsigned int))
 		return 0;
 	if (count > (prof_len+1)*sizeof(unsigned int) - p)
@@ -404,7 +203,6 @@ static ssize_t write_profile(struct file *file, const char __user *buf,
 			return -EINVAL;
 	}
 #endif
-	profile_discard_flip_buffers();
 	memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
 	return count;
 }
@@ -418,40 +216,14 @@ static const struct proc_ops profile_proc_ops = {
 int __ref create_proc_profile(void)
 {
 	struct proc_dir_entry *entry;
-#ifdef CONFIG_SMP
-	enum cpuhp_state online_state;
-#endif
-
 	int err = 0;
 
 	if (!prof_on)
 		return 0;
-#ifdef CONFIG_SMP
-	err = cpuhp_setup_state(CPUHP_PROFILE_PREPARE, "PROFILE_PREPARE",
-				profile_prepare_cpu, profile_dead_cpu);
-	if (err)
-		return err;
-
-	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PROFILE_ONLINE",
-				profile_online_cpu, NULL);
-	if (err < 0)
-		goto err_state_prep;
-	online_state = err;
-	err = 0;
-#endif
 	entry = proc_create("profile", S_IWUSR | S_IRUGO,
 			    NULL, &profile_proc_ops);
-	if (!entry)
-		goto err_state_onl;
-	proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
-
-	return err;
-err_state_onl:
-#ifdef CONFIG_SMP
-	cpuhp_remove_state(online_state);
-err_state_prep:
-	cpuhp_remove_state(CPUHP_PROFILE_PREPARE);
-#endif
+	if (entry)
+		proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
 	return err;
 }
 subsys_initcall(create_proc_profile);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a9f655025607..f3951e4a55e5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7845,6 +7845,30 @@ void set_rq_offline(struct rq *rq)
 	}
 }
 
+static inline void sched_set_rq_online(struct rq *rq, int cpu)
+{
+	struct rq_flags rf;
+
+	rq_lock_irqsave(rq, &rf);
+	if (rq->rd) {
+		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+		set_rq_online(rq);
+	}
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+static inline void sched_set_rq_offline(struct rq *rq, int cpu)
+{
+	struct rq_flags rf;
+
+	rq_lock_irqsave(rq, &rf);
+	if (rq->rd) {
+		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+		set_rq_offline(rq);
+	}
+	rq_unlock_irqrestore(rq, &rf);
+}
+
 /*
  * used to mark begin/end of suspend/resume:
  */
@@ -7895,10 +7919,25 @@ static int cpuset_cpu_inactive(unsigned int cpu)
 	return 0;
 }
 
+static inline void sched_smt_present_inc(int cpu)
+{
+#ifdef CONFIG_SCHED_SMT
+	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+		static_branch_inc_cpuslocked(&sched_smt_present);
+#endif
+}
+
+static inline void sched_smt_present_dec(int cpu)
+{
+#ifdef CONFIG_SCHED_SMT
+	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+		static_branch_dec_cpuslocked(&sched_smt_present);
+#endif
+}
+
 int sched_cpu_activate(unsigned int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
-	struct rq_flags rf;
 
 	/*
 	 * Clear the balance_push callback and prepare to schedule
@@ -7906,13 +7945,10 @@ int sched_cpu_activate(unsigned int cpu)
 	 */
 	balance_push_set(cpu, false);
 
-#ifdef CONFIG_SCHED_SMT
 	/*
 	 * When going up, increment the number of cores with SMT present.
 	 */
-	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
-		static_branch_inc_cpuslocked(&sched_smt_present);
-#endif
+	sched_smt_present_inc(cpu);
 	set_cpu_active(cpu, true);
 
 	if (sched_smp_initialized) {
@@ -7930,12 +7966,7 @@ int sched_cpu_activate(unsigned int cpu)
 	 * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
 	 *    domains.
 	 */
-	rq_lock_irqsave(rq, &rf);
-	if (rq->rd) {
-		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
-		set_rq_online(rq);
-	}
-	rq_unlock_irqrestore(rq, &rf);
+	sched_set_rq_online(rq, cpu);
 
 	return 0;
 }
@@ -7943,7 +7974,6 @@ int sched_cpu_activate(unsigned int cpu)
 int sched_cpu_deactivate(unsigned int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
-	struct rq_flags rf;
 	int ret;
 
 	/*
@@ -7974,20 +8004,14 @@ int sched_cpu_deactivate(unsigned int cpu)
 	 */
 	synchronize_rcu();
 
-	rq_lock_irqsave(rq, &rf);
-	if (rq->rd) {
-		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
-		set_rq_offline(rq);
-	}
-	rq_unlock_irqrestore(rq, &rf);
+	sched_set_rq_offline(rq, cpu);
 
-#ifdef CONFIG_SCHED_SMT
 	/*
 	 * When going down, decrement the number of cores with SMT present.
 	 */
-	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
-		static_branch_dec_cpuslocked(&sched_smt_present);
+	sched_smt_present_dec(cpu);
 
+#ifdef CONFIG_SCHED_SMT
 	sched_core_cpu_deactivate(cpu);
 #endif
 
@@ -7997,6 +8021,8 @@ int sched_cpu_deactivate(unsigned int cpu)
 	sched_update_numa(cpu, false);
 	ret = cpuset_cpu_inactive(cpu);
 	if (ret) {
+		sched_smt_present_inc(cpu);
+		sched_set_rq_online(rq, cpu);
 		balance_push_set(cpu, false);
 		set_cpu_active(cpu, true);
 		sched_update_numa(cpu, true);
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index a5e00293ae43..0bed0fa1acd9 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -582,6 +582,12 @@ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
 	}
 
 	stime = mul_u64_u64_div_u64(stime, rtime, stime + utime);
+	/*
+	 * Because mul_u64_u64_div_u64() can approximate on some
+	 * achitectures; enforce the constraint that: a*b/(b+c) <= a.
+	 */
+	if (unlikely(stime > rtime))
+		stime = rtime;
 
 update:
 	/*
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
index 78e48f5426ee..eb0cdcd4d921 100644
--- a/kernel/sched/stats.c
+++ b/kernel/sched/stats.c
@@ -92,16 +92,6 @@ void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,
 
 			trace_sched_stat_blocked(p, delta);
 
-			/*
-			 * Blocking time is in units of nanosecs, so shift by
-			 * 20 to get a milliseconds-range estimation of the
-			 * amount of time that the task spent sleeping:
-			 */
-			if (unlikely(prof_on == SLEEP_PROFILING)) {
-				profile_hits(SLEEP_PROFILING,
-					     (void *)get_wchan(p),
-					     delta >> 20);
-			}
 			account_scheduler_latency(p, delta >> 10, 0);
 		}
 	}
diff --git a/kernel/task_work.c b/kernel/task_work.c
index 5c2daa7ad3f9..5d14d639ac71 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -6,12 +6,14 @@
 
 static struct callback_head work_exited; /* all we need is ->next == NULL */
 
+#ifdef CONFIG_IRQ_WORK
 static void task_work_set_notify_irq(struct irq_work *entry)
 {
 	test_and_set_tsk_thread_flag(current, TIF_NOTIFY_RESUME);
 }
 static DEFINE_PER_CPU(struct irq_work, irq_work_NMI_resume) =
 	IRQ_WORK_INIT_HARD(task_work_set_notify_irq);
+#endif
 
 /**
  * task_work_add - ask the @task to execute @work->func()
@@ -57,6 +59,8 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
 	if (notify == TWA_NMI_CURRENT) {
 		if (WARN_ON_ONCE(task != current))
 			return -EINVAL;
+		if (!IS_ENABLED(CONFIG_IRQ_WORK))
+			return -EINVAL;
 	} else {
 		/* record the work call stack in order to print it in KASAN reports */
 		kasan_record_aux_stack(work);
@@ -81,9 +85,11 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
 	case TWA_SIGNAL_NO_IPI:
 		__set_notify_signal(task);
 		break;
+#ifdef CONFIG_IRQ_WORK
 	case TWA_NMI_CURRENT:
 		irq_work_queue(this_cpu_ptr(&irq_work_NMI_resume));
 		break;
+#endif
 	default:
 		WARN_ON_ONCE(1);
 		break;
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index d25ba49e313c..d0538a75f4c6 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -246,7 +246,7 @@ static enum wd_read_status cs_watchdog_read(struct clocksource *cs, u64 *csnow,
 
 		wd_delay = cycles_to_nsec_safe(watchdog, *wdnow, wd_end);
 		if (wd_delay <= WATCHDOG_MAX_SKEW) {
-			if (nretries > 1 || nretries >= max_retries) {
+			if (nretries > 1 && nretries >= max_retries) {
 				pr_warn("timekeeping watchdog on CPU%d: %s retried %d times before success\n",
 					smp_processor_id(), watchdog->name, nretries);
 			}
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 406dccb79c2b..8d2dd214ec68 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -727,17 +727,16 @@ static inline void process_adjtimex_modes(const struct __kernel_timex *txc,
 	}
 
 	if (txc->modes & ADJ_MAXERROR)
-		time_maxerror = txc->maxerror;
+		time_maxerror = clamp(txc->maxerror, 0, NTP_PHASE_LIMIT);
 
 	if (txc->modes & ADJ_ESTERROR)
-		time_esterror = txc->esterror;
+		time_esterror = clamp(txc->esterror, 0, NTP_PHASE_LIMIT);
 
 	if (txc->modes & ADJ_TIMECONST) {
-		time_constant = txc->constant;
+		time_constant = clamp(txc->constant, 0, MAXTC);
 		if (!(time_status & STA_NANO))
 			time_constant += 4;
-		time_constant = min(time_constant, (long)MAXTC);
-		time_constant = max(time_constant, 0l);
+		time_constant = clamp(time_constant, 0, MAXTC);
 	}
 
 	if (txc->modes & ADJ_TAI &&
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index b4843099a8da..ed58eebb4e8f 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -1141,7 +1141,6 @@ void tick_broadcast_switch_to_oneshot(void)
 #ifdef CONFIG_HOTPLUG_CPU
 void hotplug_cpu__broadcast_tick_pull(int deadcpu)
 {
-	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
 	struct clock_event_device *bc;
 	unsigned long flags;
 
@@ -1167,6 +1166,8 @@ void hotplug_cpu__broadcast_tick_pull(int deadcpu)
 		 * device to avoid the starvation.
 		 */
 		if (tick_check_broadcast_expired()) {
+			struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+
 			cpumask_clear_cpu(smp_processor_id(), tick_broadcast_force_mask);
 			tick_program_event(td->evtdev->next_event, 1);
 		}
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 2fa87dcfeda9..5391e4167d60 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -2606,7 +2606,7 @@ int do_adjtimex(struct __kernel_timex *txc)
 		clock_set |= timekeeping_advance(TK_ADV_FREQ);
 
 	if (clock_set)
-		clock_was_set(CLOCK_REALTIME);
+		clock_was_set(CLOCK_SET_WALL);
 
 	ntp_notify_cmos_timer();
 
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index fc205ad167a9..d1d5ea2d0a1b 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -902,7 +902,7 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 
 	i = *idx ? : task->curr_ret_stack;
 	while (i > 0) {
-		ret_stack = get_ret_stack(current, i, &i);
+		ret_stack = get_ret_stack(task, i, &i);
 		if (!ret_stack)
 			break;
 		/*
diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c
index cb0871fbdb07..314ffc143039 100644
--- a/kernel/trace/preemptirq_delay_test.c
+++ b/kernel/trace/preemptirq_delay_test.c
@@ -34,8 +34,6 @@ MODULE_PARM_DESC(cpu_affinity, "Cpu num test is running on");
 
 static struct completion done;
 
-#define MIN(x, y) ((x) < (y) ? (x) : (y))
-
 static void busy_wait(ulong time)
 {
 	u64 start, end;
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 28853966aa9a..cebd879a30cb 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -693,18 +693,6 @@ u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
 }
 
 /**
- * ring_buffer_nr_pages - get the number of buffer pages in the ring buffer
- * @buffer: The ring_buffer to get the number of pages from
- * @cpu: The cpu of the ring_buffer to get the number of pages from
- *
- * Returns the number of pages used by a per_cpu buffer of the ring buffer.
- */
-size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu)
-{
-	return buffer->buffers[cpu]->nr_pages;
-}
-
-/**
  * ring_buffer_nr_dirty_pages - get the number of used pages in the ring buffer
  * @buffer: The ring_buffer to get the number of pages from
  * @cpu: The cpu of the ring_buffer to get the number of pages from
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 10cd38bce2f1..ebe7ce2f5f4a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7956,7 +7956,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 	trace_access_unlock(iter->cpu_file);
 
 	if (ret < 0) {
-		if (trace_empty(iter)) {
+		if (trace_empty(iter) && !iter->closed) {
 			if ((filp->f_flags & O_NONBLOCK))
 				return -EAGAIN;
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8783bebd0562..bd3e3069300e 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1634,6 +1634,29 @@ static inline void *event_file_data(struct file *filp)
 extern struct mutex event_mutex;
 extern struct list_head ftrace_events;
 
+/*
+ * When the trace_event_file is the filp->i_private pointer,
+ * it must be taken under the event_mutex lock, and then checked
+ * if the EVENT_FILE_FL_FREED flag is set. If it is, then the
+ * data pointed to by the trace_event_file can not be trusted.
+ *
+ * Use the event_file_file() to access the trace_event_file from
+ * the filp the first time under the event_mutex and check for
+ * NULL. If it is needed to be retrieved again and the event_mutex
+ * is still held, then the event_file_data() can be used and it
+ * is guaranteed to be valid.
+ */
+static inline struct trace_event_file *event_file_file(struct file *filp)
+{
+	struct trace_event_file *file;
+
+	lockdep_assert_held(&event_mutex);
+	file = READ_ONCE(file_inode(filp)->i_private);
+	if (!file || file->flags & EVENT_FILE_FL_FREED)
+		return NULL;
+	return file;
+}
+
 extern const struct file_operations event_trigger_fops;
 extern const struct file_operations event_hist_fops;
 extern const struct file_operations event_hist_debug_fops;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 6ef29eba90ce..7266ec2a4eea 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -992,18 +992,18 @@ static void remove_subsystem(struct trace_subsystem_dir *dir)
 
 void event_file_get(struct trace_event_file *file)
 {
-	atomic_inc(&file->ref);
+	refcount_inc(&file->ref);
 }
 
 void event_file_put(struct trace_event_file *file)
 {
-	if (WARN_ON_ONCE(!atomic_read(&file->ref))) {
+	if (WARN_ON_ONCE(!refcount_read(&file->ref))) {
 		if (file->flags & EVENT_FILE_FL_FREED)
 			kmem_cache_free(file_cachep, file);
 		return;
 	}
 
-	if (atomic_dec_and_test(&file->ref)) {
+	if (refcount_dec_and_test(&file->ref)) {
 		/* Count should only go to zero when it is freed */
 		if (WARN_ON_ONCE(!(file->flags & EVENT_FILE_FL_FREED)))
 			return;
@@ -1386,12 +1386,12 @@ event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 	char buf[4] = "0";
 
 	mutex_lock(&event_mutex);
-	file = event_file_data(filp);
+	file = event_file_file(filp);
 	if (likely(file))
 		flags = file->flags;
 	mutex_unlock(&event_mutex);
 
-	if (!file || flags & EVENT_FILE_FL_FREED)
+	if (!file)
 		return -ENODEV;
 
 	if (flags & EVENT_FILE_FL_ENABLED &&
@@ -1424,8 +1424,8 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	case 1:
 		ret = -ENODEV;
 		mutex_lock(&event_mutex);
-		file = event_file_data(filp);
-		if (likely(file && !(file->flags & EVENT_FILE_FL_FREED))) {
+		file = event_file_file(filp);
+		if (likely(file)) {
 			ret = tracing_update_buffers(file->tr);
 			if (ret < 0) {
 				mutex_unlock(&event_mutex);
@@ -1540,7 +1540,8 @@ enum {
 
 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 {
-	struct trace_event_call *call = event_file_data(m->private);
+	struct trace_event_file *file = event_file_data(m->private);
+	struct trace_event_call *call = file->event_call;
 	struct list_head *common_head = &ftrace_common_fields;
 	struct list_head *head = trace_get_fields(call);
 	struct list_head *node = v;
@@ -1572,7 +1573,8 @@ static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 
 static int f_show(struct seq_file *m, void *v)
 {
-	struct trace_event_call *call = event_file_data(m->private);
+	struct trace_event_file *file = event_file_data(m->private);
+	struct trace_event_call *call = file->event_call;
 	struct ftrace_event_field *field;
 	const char *array_descriptor;
 
@@ -1627,12 +1629,14 @@ static int f_show(struct seq_file *m, void *v)
 
 static void *f_start(struct seq_file *m, loff_t *pos)
 {
+	struct trace_event_file *file;
 	void *p = (void *)FORMAT_HEADER;
 	loff_t l = 0;
 
 	/* ->stop() is called even if ->start() fails */
 	mutex_lock(&event_mutex);
-	if (!event_file_data(m->private))
+	file = event_file_file(m->private);
+	if (!file)
 		return ERR_PTR(-ENODEV);
 
 	while (l < *pos && p)
@@ -1706,8 +1710,8 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 	trace_seq_init(s);
 
 	mutex_lock(&event_mutex);
-	file = event_file_data(filp);
-	if (file && !(file->flags & EVENT_FILE_FL_FREED))
+	file = event_file_file(filp);
+	if (file)
 		print_event_filter(file, s);
 	mutex_unlock(&event_mutex);
 
@@ -1736,9 +1740,13 @@ event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 		return PTR_ERR(buf);
 
 	mutex_lock(&event_mutex);
-	file = event_file_data(filp);
-	if (file)
-		err = apply_event_filter(file, buf);
+	file = event_file_file(filp);
+	if (file) {
+		if (file->flags & EVENT_FILE_FL_FREED)
+			err = -ENODEV;
+		else
+			err = apply_event_filter(file, buf);
+	}
 	mutex_unlock(&event_mutex);
 
 	kfree(buf);
@@ -2485,7 +2493,6 @@ static int event_callback(const char *name, umode_t *mode, void **data,
 	if (strcmp(name, "format") == 0) {
 		*mode = TRACE_MODE_READ;
 		*fops = &ftrace_event_format_fops;
-		*data = call;
 		return 1;
 	}
 
@@ -2996,7 +3003,7 @@ trace_create_new_event(struct trace_event_call *call,
 	atomic_set(&file->tm_ref, 0);
 	INIT_LIST_HEAD(&file->triggers);
 	list_add(&file->list, &tr->events);
-	event_file_get(file);
+	refcount_set(&file->ref, 1);
 
 	return file;
 }
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 6ece1308d36a..5f9119eb7c67 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -5601,7 +5601,7 @@ static int hist_show(struct seq_file *m, void *v)
 
 	mutex_lock(&event_mutex);
 
-	event_file = event_file_data(m->private);
+	event_file = event_file_file(m->private);
 	if (unlikely(!event_file)) {
 		ret = -ENODEV;
 		goto out_unlock;
@@ -5880,7 +5880,7 @@ static int hist_debug_show(struct seq_file *m, void *v)
 
 	mutex_lock(&event_mutex);
 
-	event_file = event_file_data(m->private);
+	event_file = event_file_file(m->private);
 	if (unlikely(!event_file)) {
 		ret = -ENODEV;
 		goto out_unlock;
diff --git a/kernel/trace/trace_events_inject.c b/kernel/trace/trace_events_inject.c
index 8650562bdaa9..a8f076809db4 100644
--- a/kernel/trace/trace_events_inject.c
+++ b/kernel/trace/trace_events_inject.c
@@ -299,7 +299,7 @@ event_inject_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	strim(buf);
 
 	mutex_lock(&event_mutex);
-	file = event_file_data(filp);
+	file = event_file_file(filp);
 	if (file) {
 		call = file->event_call;
 		size = parse_entry(buf, call, &entry);
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 4bec043c8690..a5e3d6acf1e1 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -159,7 +159,7 @@ static void *trigger_start(struct seq_file *m, loff_t *pos)
 
 	/* ->stop() is called even if ->start() fails */
 	mutex_lock(&event_mutex);
-	event_file = event_file_data(m->private);
+	event_file = event_file_file(m->private);
 	if (unlikely(!event_file))
 		return ERR_PTR(-ENODEV);
 
@@ -213,7 +213,7 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file)
 
 	mutex_lock(&event_mutex);
 
-	if (unlikely(!event_file_data(file))) {
+	if (unlikely(!event_file_file(file))) {
 		mutex_unlock(&event_mutex);
 		return -ENODEV;
 	}
@@ -293,7 +293,7 @@ static ssize_t event_trigger_regex_write(struct file *file,
 	strim(buf);
 
 	mutex_lock(&event_mutex);
-	event_file = event_file_data(file);
+	event_file = event_file_file(file);
 	if (unlikely(!event_file)) {
 		mutex_unlock(&event_mutex);
 		kfree(buf);
diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
index a4dcf0f24352..3a56e7c8aa4f 100644
--- a/kernel/trace/tracing_map.c
+++ b/kernel/trace/tracing_map.c
@@ -454,7 +454,7 @@ static struct tracing_map_elt *get_free_elt(struct tracing_map *map)
 	struct tracing_map_elt *elt = NULL;
 	int idx;
 
-	idx = atomic_inc_return(&map->next_elt);
+	idx = atomic_fetch_add_unless(&map->next_elt, 1, map->max_elts);
 	if (idx < map->max_elts) {
 		elt = *(TRACING_MAP_ELT(map->elts, idx));
 		if (map->ops && map->ops->elt_init)
@@ -699,7 +699,7 @@ void tracing_map_clear(struct tracing_map *map)
 {
 	unsigned int i;
 
-	atomic_set(&map->next_elt, -1);
+	atomic_set(&map->next_elt, 0);
 	atomic64_set(&map->hits, 0);
 	atomic64_set(&map->drops, 0);
 
@@ -783,7 +783,7 @@ struct tracing_map *tracing_map_create(unsigned int map_bits,
 
 	map->map_bits = map_bits;
 	map->max_elts = (1 << map_bits);
-	atomic_set(&map->next_elt, -1);
+	atomic_set(&map->next_elt, 0);
 
 	map->map_size = (1 << (map_bits + 1));
 	map->ops = ops;
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 1745ca788ede..e7b005ff3750 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -377,7 +377,7 @@ struct workqueue_struct {
 
 	/* hot fields used during command issue, aligned to cacheline */
 	unsigned int		flags ____cacheline_aligned; /* WQ: WQ_* flags */
-	struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */
+	struct pool_workqueue __rcu * __percpu *cpu_pwq; /* I: per-cpu pwqs */
 	struct wq_node_nr_active *node_nr_active[]; /* I: per-node nr_active */
 };
 
@@ -897,7 +897,7 @@ static struct worker_pool *get_work_pool(struct work_struct *work)
 
 static unsigned long shift_and_mask(unsigned long v, u32 shift, u32 bits)
 {
-	return (v >> shift) & ((1 << bits) - 1);
+	return (v >> shift) & ((1U << bits) - 1);
 }
 
 static void work_offqd_unpack(struct work_offq_data *offqd, unsigned long data)
@@ -3351,7 +3351,6 @@ woke_up:
 		set_pf_worker(false);
 
 		ida_free(&pool->worker_ida, worker->id);
-		WARN_ON_ONCE(!list_empty(&worker->entry));
 		return 0;
 	}
 
@@ -4167,7 +4166,6 @@ already_gone:
 static bool __flush_work(struct work_struct *work, bool from_cancel)
 {
 	struct wq_barrier barr;
-	unsigned long data;
 
 	if (WARN_ON(!wq_online))
 		return false;
@@ -4185,29 +4183,35 @@ static bool __flush_work(struct work_struct *work, bool from_cancel)
 	 * was queued on a BH workqueue, we also know that it was running in the
 	 * BH context and thus can be busy-waited.
 	 */
-	data = *work_data_bits(work);
-	if (from_cancel &&
-	    !WARN_ON_ONCE(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_BH)) {
-		/*
-		 * On RT, prevent a live lock when %current preempted soft
-		 * interrupt processing or prevents ksoftirqd from running by
-		 * keeping flipping BH. If the BH work item runs on a different
-		 * CPU then this has no effect other than doing the BH
-		 * disable/enable dance for nothing. This is copied from
-		 * kernel/softirq.c::tasklet_unlock_spin_wait().
-		 */
-		while (!try_wait_for_completion(&barr.done)) {
-			if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
-				local_bh_disable();
-				local_bh_enable();
-			} else {
-				cpu_relax();
+	if (from_cancel) {
+		unsigned long data = *work_data_bits(work);
+
+		if (!WARN_ON_ONCE(data & WORK_STRUCT_PWQ) &&
+		    (data & WORK_OFFQ_BH)) {
+			/*
+			 * On RT, prevent a live lock when %current preempted
+			 * soft interrupt processing or prevents ksoftirqd from
+			 * running by keeping flipping BH. If the BH work item
+			 * runs on a different CPU then this has no effect other
+			 * than doing the BH disable/enable dance for nothing.
+			 * This is copied from
+			 * kernel/softirq.c::tasklet_unlock_spin_wait().
+			 */
+			while (!try_wait_for_completion(&barr.done)) {
+				if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+					local_bh_disable();
+					local_bh_enable();
+				} else {
+					cpu_relax();
+				}
 			}
+			goto out_destroy;
 		}
-	} else {
-		wait_for_completion(&barr.done);
 	}
 
+	wait_for_completion(&barr.done);
+
+out_destroy:
 	destroy_work_on_stack(&barr.work);
 	return true;
 }