diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
index 7364de008bab395762358fdfddf5aa8d8e2c13c5..91b8a8378ba39018ac854a54dc2f3eeb3613d1f2 100644
--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -59,6 +59,7 @@ struct insn_emulation {
 static LIST_HEAD(insn_emulation);
 static int nr_insn_emulated __initdata;
 static DEFINE_RAW_SPINLOCK(insn_emulation_lock);
+static DEFINE_MUTEX(insn_emulation_mutex);
 
 static void register_emulation_hooks(struct insn_emulation_ops *ops)
 {
@@ -207,10 +208,10 @@ static int emulation_proc_handler(struct ctl_table *table, int write,
 				  loff_t *ppos)
 {
 	int ret = 0;
-	struct insn_emulation *insn = (struct insn_emulation *) table->data;
+	struct insn_emulation *insn = container_of(table->data, struct insn_emulation, current_mode);
 	enum insn_emulation_mode prev_mode = insn->current_mode;
 
-	table->data = &insn->current_mode;
+	mutex_lock(&insn_emulation_mutex);
 	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 
 	if (ret || !write || prev_mode == insn->current_mode)
@@ -223,7 +224,7 @@ static int emulation_proc_handler(struct ctl_table *table, int write,
 		update_insn_emulation_mode(insn, INSN_UNDEF);
 	}
 ret:
-	table->data = insn;
+	mutex_unlock(&insn_emulation_mutex);
 	return ret;
 }
 
@@ -247,7 +248,7 @@ static void __init register_insn_emulation_sysctl(void)
 		sysctl->maxlen = sizeof(int);
 
 		sysctl->procname = insn->ops->name;
-		sysctl->data = insn;
+		sysctl->data = &insn->current_mode;
 		sysctl->extra1 = &insn->min;
 		sysctl->extra2 = &insn->max;
 		sysctl->proc_handler = emulation_proc_handler;
diff --git a/drivers/hid/hid-roccat.c b/drivers/hid/hid-roccat.c
index 26373b82fe812510a6755a15ef96755e3396231e..6da80e442fdd1065ed5b5e8b871e402f74b099cf 100644
--- a/drivers/hid/hid-roccat.c
+++ b/drivers/hid/hid-roccat.c
@@ -257,6 +257,8 @@ int roccat_report_event(int minor, u8 const *data)
 	if (!new_value)
 		return -ENOMEM;
 
+	mutex_lock(&device->cbuf_lock);
+
 	report = &device->cbuf[device->cbuf_end];
 
 	/* passing NULL is safe */
@@ -276,6 +278,8 @@ int roccat_report_event(int minor, u8 const *data)
 			reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
 	}
 
+	mutex_unlock(&device->cbuf_lock);
+
 	wake_up_interruptible(&device->wait);
 	return 0;
 }
diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index 5144888ae36f7d6df3648190b4fe90a878fd9d8a..399639c3cb82308498c6673b23569ae8d235049f 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -3875,6 +3875,8 @@ static int em28xx_usb_probe(struct usb_interface *intf,
 		goto err_free;
 	}
 
+	kref_init(&dev->ref);
+
 	dev->devno = nr;
 	dev->model = id->driver_info;
 	dev->alt   = -1;
@@ -3975,6 +3977,8 @@ static int em28xx_usb_probe(struct usb_interface *intf,
 	}
 
 	if (dev->board.has_dual_ts && em28xx_duplicate_dev(dev) == 0) {
+		kref_init(&dev->dev_next->ref);
+
 		dev->dev_next->ts = SECONDARY_TS;
 		dev->dev_next->alt   = -1;
 		dev->dev_next->is_audio_only = has_vendor_audio &&
@@ -4029,12 +4033,8 @@ static int em28xx_usb_probe(struct usb_interface *intf,
 			em28xx_write_reg(dev, 0x0b, 0x82);
 			mdelay(100);
 		}
-
-		kref_init(&dev->dev_next->ref);
 	}
 
-	kref_init(&dev->ref);
-
 	request_modules(dev);
 
 	/*
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 8d04e7deedc66be25c7de941f962d0816fd41053..297744ea4dd0cc266d8024282a76bfd4d4a00610 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -39,12 +39,15 @@ struct anon_vma {
 	atomic_t refcount;
 
 	/*
-	 * Count of child anon_vmas and VMAs which points to this anon_vma.
+	 * Count of child anon_vmas. Equals to the count of all anon_vmas that
+	 * have ->parent pointing to this one, including itself.
 	 *
 	 * This counter is used for making decision about reusing anon_vma
 	 * instead of forking new one. See comments in function anon_vma_clone.
 	 */
-	unsigned degree;
+	unsigned long num_children;
+	/* Count of VMAs whose ->anon_vma pointer points to this object. */
+	unsigned long num_active_vmas;
 
 	struct anon_vma *parent;	/* Parent of this anon_vma */
 
diff --git a/mm/mremap.c b/mm/mremap.c
index 138abbae4f758763c5be19578b2909d5d003db28..6d18741914fbf047f56fdfe695c4863b5d509a42 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -307,12 +307,10 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 			 */
 			bool moved;
 
-			if (need_rmap_locks)
-				take_rmap_locks(vma);
+			take_rmap_locks(vma);
 			moved = move_normal_pmd(vma, old_addr, new_addr,
 						old_pmd, new_pmd);
-			if (need_rmap_locks)
-				drop_rmap_locks(vma);
+			drop_rmap_locks(vma);
 			if (moved)
 				continue;
 #endif
diff --git a/mm/rmap.c b/mm/rmap.c
index cdf549f6f617c43d0beec58e7e663f898ae850b7..d901480a5b0ea21815a0a4921bc73874a0597ebf 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -89,7 +89,8 @@ static inline struct anon_vma *anon_vma_alloc(void)
 	anon_vma = kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL);
 	if (anon_vma) {
 		atomic_set(&anon_vma->refcount, 1);
-		anon_vma->degree = 1;	/* Reference for first vma */
+		anon_vma->num_children = 0;
+		anon_vma->num_active_vmas = 0;
 		anon_vma->parent = anon_vma;
 		/*
 		 * Initialise the anon_vma root to point to itself. If called
@@ -197,6 +198,7 @@ int __anon_vma_prepare(struct vm_area_struct *vma)
 		anon_vma = anon_vma_alloc();
 		if (unlikely(!anon_vma))
 			goto out_enomem_free_avc;
+		anon_vma->num_children++; /* self-parent link for new root */
 		allocated = anon_vma;
 	}
 
@@ -206,8 +208,7 @@ int __anon_vma_prepare(struct vm_area_struct *vma)
 	if (likely(!vma->anon_vma)) {
 		vma->anon_vma = anon_vma;
 		anon_vma_chain_link(vma, avc, anon_vma);
-		/* vma reference or self-parent link for new root */
-		anon_vma->degree++;
+		anon_vma->num_active_vmas++;
 		allocated = NULL;
 		avc = NULL;
 	}
@@ -292,19 +293,19 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
 		anon_vma_chain_link(dst, avc, anon_vma);
 
 		/*
-		 * Reuse existing anon_vma if its degree lower than two,
-		 * that means it has no vma and only one anon_vma child.
+		 * Reuse existing anon_vma if it has no vma and only one
+		 * anon_vma child.
 		 *
-		 * Do not chose parent anon_vma, otherwise first child
-		 * will always reuse it. Root anon_vma is never reused:
+		 * Root anon_vma is never reused:
 		 * it has self-parent reference and at least one child.
 		 */
 		if (!dst->anon_vma && src->anon_vma &&
-		    anon_vma != src->anon_vma && anon_vma->degree < 2)
+		    anon_vma->num_children < 2 &&
+		    anon_vma->num_active_vmas == 0)
 			dst->anon_vma = anon_vma;
 	}
 	if (dst->anon_vma)
-		dst->anon_vma->degree++;
+		dst->anon_vma->num_active_vmas++;
 	unlock_anon_vma_root(root);
 	return 0;
 
@@ -354,6 +355,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
 	anon_vma = anon_vma_alloc();
 	if (!anon_vma)
 		goto out_error;
+	anon_vma->num_active_vmas++;
 	avc = anon_vma_chain_alloc(GFP_KERNEL);
 	if (!avc)
 		goto out_error_free_anon_vma;
@@ -374,7 +376,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
 	vma->anon_vma = anon_vma;
 	anon_vma_lock_write(anon_vma);
 	anon_vma_chain_link(vma, avc, anon_vma);
-	anon_vma->parent->degree++;
+	anon_vma->parent->num_children++;
 	anon_vma_unlock_write(anon_vma);
 
 	return 0;
@@ -406,7 +408,7 @@ void unlink_anon_vmas(struct vm_area_struct *vma)
 		 * to free them outside the lock.
 		 */
 		if (RB_EMPTY_ROOT(&anon_vma->rb_root.rb_root)) {
-			anon_vma->parent->degree--;
+			anon_vma->parent->num_children--;
 			continue;
 		}
 
@@ -414,7 +416,7 @@ void unlink_anon_vmas(struct vm_area_struct *vma)
 		anon_vma_chain_free(avc);
 	}
 	if (vma->anon_vma) {
-		vma->anon_vma->degree--;
+		vma->anon_vma->num_active_vmas--;
 
 		/*
 		 * vma would still be needed after unlink, and anon_vma will be prepared
@@ -432,7 +434,8 @@ void unlink_anon_vmas(struct vm_area_struct *vma)
 	list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
 		struct anon_vma *anon_vma = avc->anon_vma;
 
-		VM_WARN_ON(anon_vma->degree);
+		VM_WARN_ON(anon_vma->num_children);
+		VM_WARN_ON(anon_vma->num_active_vmas);
 		put_anon_vma(anon_vma);
 
 		list_del(&avc->same_vma);
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index 142fc751a84770111679f23d740a919c3377144c..339f115d1af02834e2640fa36428bb367099585e 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -1645,13 +1645,14 @@ static int snd_pcm_oss_sync(struct snd_pcm_oss_file *pcm_oss_file)
 		runtime = substream->runtime;
 		if (atomic_read(&substream->mmap_count))
 			goto __direct;
-		if ((err = snd_pcm_oss_make_ready(substream)) < 0)
-			return err;
 		atomic_inc(&runtime->oss.rw_ref);
 		if (mutex_lock_interruptible(&runtime->oss.params_lock)) {
 			atomic_dec(&runtime->oss.rw_ref);
 			return -ERESTARTSYS;
 		}
+		err = snd_pcm_oss_make_ready_locked(substream);
+		if (err < 0)
+			goto unlock;
 		format = snd_pcm_oss_format_from(runtime->oss.format);
 		width = snd_pcm_format_physical_width(format);
 		if (runtime->oss.buffer_used > 0) {