uprobes: misc

index b52376d..f0d0453 100644
@@ -99,7 +99,8 @@ static bool valid_vma(struct vm_area_struct *vma, bool is_register)
 	if (!is_register)
 		return true;
 
-	if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) == (VM_READ|VM_EXEC))
+	if ((vma->vm_flags & (VM_HUGETLB|VM_READ|VM_WRITE|VM_EXEC|VM_SHARED))
+				== (VM_READ|VM_EXEC))
 		return true;
 
 	return false;

index b52376d..f0d0453 100644
@@ -99,7 +99,8 @@ static bool valid_vma(struct vm_area_struct *vma, bool is_register)
 	if (!is_register)
 		return true;
 
-	if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) == (VM_READ|VM_EXEC))
+	if ((vma->vm_flags & (VM_HUGETLB|VM_READ|VM_WRITE|VM_EXEC|VM_SHARED))
+				== (VM_READ|VM_EXEC))
 		return true;
 
 	return false;

index f0d0453..604930b 100644
@@ -610,6 +610,9 @@ __copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *ins
 	if (!filp)
 		return -EINVAL;
 
+	if (!mapping->a_ops->readpage)
+		return -EIO;
+
 	idx = (unsigned long)(offset >> PAGE_CACHE_SHIFT);
 	off1 = offset &= ~PAGE_MASK;
 

index f0d0453..604930b 100644
@@ -610,6 +610,9 @@ __copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *ins
 	if (!filp)
 		return -EINVAL;
 
+	if (!mapping->a_ops->readpage)
+		return -EIO;
+
 	idx = (unsigned long)(offset >> PAGE_CACHE_SHIFT);
 	off1 = offset &= ~PAGE_MASK;
 

index 604930b..3ccdb29 100644
@@ -129,33 +129,17 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)
 static int __replace_page(struct vm_area_struct *vma, struct page *page, struct page *kpage)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *ptep;
-	spinlock_t *ptl;
 	unsigned long addr;
-	int err = -EFAULT;
+	spinlock_t *ptl;
+	pte_t *ptep;
 
 	addr = page_address_in_vma(page, vma);
 	if (addr == -EFAULT)
-		goto out;
-
-	pgd = pgd_offset(mm, addr);
-	if (!pgd_present(*pgd))
-		goto out;
-
-	pud = pud_offset(pgd, addr);
-	if (!pud_present(*pud))
-		goto out;
+		return -EFAULT;
 
-	pmd = pmd_offset(pud, addr);
-	if (!pmd_present(*pmd))
-		goto out;
-
-	ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
+	ptep = page_check_address(page, mm, addr, &ptl, 0);
 	if (!ptep)
-		goto out;
+		return -EAGAIN;
 
 	get_page(kpage);
 	page_add_new_anon_rmap(kpage, vma, addr);

@@ -174,10 +158,8 @@ static int __replace_page(struct vm_area_struct *vma, struct page *page, struct
 		try_to_free_swap(page);
 	put_page(page);
 	pte_unmap_unlock(ptep, ptl);
-	err = 0;
 
-out:
-	return err;
+	return 0;
 }
 
 /**

@@ -222,9 +204,10 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	void *vaddr_old, *vaddr_new;
 	struct vm_area_struct *vma;
 	struct uprobe *uprobe;
+	unsigned long pgoff;
 	loff_t addr;
 	int ret;
-
+retry:
 	/* Read the page with vaddr into memory */
 	ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma);
 	if (ret <= 0)

@@ -269,9 +252,9 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	memcpy(vaddr_new, vaddr_old, PAGE_SIZE);
 
 	/* poke the new insn in, ASSUMES we don't cross page boundary */
-	vaddr &= ~PAGE_MASK;
-	BUG_ON(vaddr + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
-	memcpy(vaddr_new + vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
+	pgoff = (vaddr & ~PAGE_MASK);
+	BUG_ON(pgoff + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
+	memcpy(vaddr_new + pgoff, &opcode, UPROBE_SWBP_INSN_SIZE);
 
 	kunmap_atomic(vaddr_new);
 	kunmap_atomic(vaddr_old);

@@ -291,6 +274,8 @@ unlock_out:
 put_out:
 	put_page(old_page);
 
+	if (unlikely(ret == -EAGAIN))
+		goto retry;
 	return ret;
 }
 

index 604930b..3ccdb29 100644
@@ -129,33 +129,17 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)
 static int __replace_page(struct vm_area_struct *vma, struct page *page, struct page *kpage)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *ptep;
-	spinlock_t *ptl;
 	unsigned long addr;
-	int err = -EFAULT;
+	spinlock_t *ptl;
+	pte_t *ptep;
 
 	addr = page_address_in_vma(page, vma);
 	if (addr == -EFAULT)
-		goto out;
-
-	pgd = pgd_offset(mm, addr);
-	if (!pgd_present(*pgd))
-		goto out;
-
-	pud = pud_offset(pgd, addr);
-	if (!pud_present(*pud))
-		goto out;
+		return -EFAULT;
 
-	pmd = pmd_offset(pud, addr);
-	if (!pmd_present(*pmd))
-		goto out;
-
-	ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
+	ptep = page_check_address(page, mm, addr, &ptl, 0);
 	if (!ptep)
-		goto out;
+		return -EAGAIN;
 
 	get_page(kpage);
 	page_add_new_anon_rmap(kpage, vma, addr);

@@ -174,10 +158,8 @@ static int __replace_page(struct vm_area_struct *vma, struct page *page, struct
 		try_to_free_swap(page);
 	put_page(page);
 	pte_unmap_unlock(ptep, ptl);
-	err = 0;
 
-out:
-	return err;
+	return 0;
 }
 
 /**

@@ -222,9 +204,10 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	void *vaddr_old, *vaddr_new;
 	struct vm_area_struct *vma;
 	struct uprobe *uprobe;
+	unsigned long pgoff;
 	loff_t addr;
 	int ret;
-
+retry:
 	/* Read the page with vaddr into memory */
 	ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma);
 	if (ret <= 0)

@@ -269,9 +252,9 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	memcpy(vaddr_new, vaddr_old, PAGE_SIZE);
 
 	/* poke the new insn in, ASSUMES we don't cross page boundary */
-	vaddr &= ~PAGE_MASK;
-	BUG_ON(vaddr + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
-	memcpy(vaddr_new + vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
+	pgoff = (vaddr & ~PAGE_MASK);
+	BUG_ON(pgoff + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
+	memcpy(vaddr_new + pgoff, &opcode, UPROBE_SWBP_INSN_SIZE);
 
 	kunmap_atomic(vaddr_new);
 	kunmap_atomic(vaddr_old);

@@ -291,6 +274,8 @@ unlock_out:
 put_out:
 	put_page(old_page);
 
+	if (unlikely(ret == -EAGAIN))
+		goto retry;
 	return ret;
 }
 

index 3ccdb29..ec78152 100644
@@ -693,7 +693,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 			return ret;
 
 		if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
-			return -EEXIST;
+			return -ENOTSUPP;
 
 		ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, addr);
 		if (ret)

index 3ccdb29..ec78152 100644
@@ -693,7 +693,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 			return ret;
 
 		if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
-			return -EEXIST;
+			return -ENOTSUPP;
 
 		ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, addr);
 		if (ret)

index ec78152..4e0db34 100644
@@ -60,17 +60,6 @@ static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
  */
 static atomic_t uprobe_events = ATOMIC_INIT(0);
 
-/*
- * Maintain a temporary per vma info that can be used to search if a vma
- * has already been handled. This structure is introduced since extending
- * vm_area_struct wasnt recommended.
- */
-struct vma_info {
-	struct list_head	probe_list;
-	struct mm_struct	*mm;
-	loff_t			vaddr;
-};
-
 struct uprobe {
 	struct rb_node		rb_node;	/* node in the rb tree */
 	atomic_t		ref;

@@ -742,139 +731,123 @@ static void delete_uprobe(struct uprobe *uprobe)
 	atomic_dec(&uprobe_events);
 }
 
-static struct vma_info *
-__find_next_vma_info(struct address_space *mapping, struct list_head *head,
-			struct vma_info *vi, loff_t offset, bool is_register)
+struct map_info {
+	struct map_info *next;
+	struct mm_struct *mm;
+	loff_t vaddr;
+};
+
+static inline struct map_info *free_map_info(struct map_info *info)
 {
+	struct map_info *next = info->next;
+	kfree(info);
+	return next;
+}
+
+static struct map_info *
+build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
+{
+	unsigned long pgoff = offset >> PAGE_SHIFT;
 	struct prio_tree_iter iter;
 	struct vm_area_struct *vma;
-	struct vma_info *tmpvi;
-	unsigned long pgoff;
-	int existing_vma;
-	loff_t vaddr;
-
-	pgoff = offset >> PAGE_SHIFT;
+	struct map_info *curr = NULL;
+	struct map_info *prev = NULL;
+	struct map_info *info;
+	int more = 0;
 
+ again:
+	mutex_lock(&mapping->i_mmap_mutex);
 	vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
 		if (!valid_vma(vma, is_register))
 			continue;
 
-		existing_vma = 0;
-		vaddr = vma_address(vma, offset);
-
-		list_for_each_entry(tmpvi, head, probe_list) {
-			if (tmpvi->mm == vma->vm_mm && tmpvi->vaddr == vaddr) {
-				existing_vma = 1;
-				break;
-			}
-		}
-
-		/*
-		 * Another vma needs a probe to be installed. However skip
-		 * installing the probe if the vma is about to be unlinked.
-		 */
-		if (!existing_vma && atomic_inc_not_zero(&vma->vm_mm->mm_users)) {
-			vi->mm = vma->vm_mm;
-			vi->vaddr = vaddr;
-			list_add(&vi->probe_list, head);
-
-			return vi;
+		if (!prev) {
+			more++;
+			continue;
 		}
-	}
-
-	return NULL;
-}
 
-/*
- * Iterate in the rmap prio tree  and find a vma where a probe has not
- * yet been inserted.
- */
-static struct vma_info *
-find_next_vma_info(struct address_space *mapping, struct list_head *head,
-		loff_t offset, bool is_register)
-{
-	struct vma_info *vi, *retvi;
+		if (!atomic_inc_not_zero(&vma->vm_mm->mm_users))
+			continue;
 
-	vi = kzalloc(sizeof(struct vma_info), GFP_KERNEL);
-	if (!vi)
-		return ERR_PTR(-ENOMEM);
+		info = prev;
+		prev = prev->next;
+		info->next = curr;
+		curr = info;
 
-	mutex_lock(&mapping->i_mmap_mutex);
-	retvi = __find_next_vma_info(mapping, head, vi, offset, is_register);
+		info->mm = vma->vm_mm;
+		info->vaddr = vma_address(vma, offset);
+	}
 	mutex_unlock(&mapping->i_mmap_mutex);
 
-	if (!retvi)
-		kfree(vi);
+	if (!more)
+		goto out;
+
+	prev = curr;
+	while (curr) {
+		mmput(curr->mm);
+		curr = curr->next;
+	}
 
-	return retvi;
+	do {
+		info = kmalloc(sizeof(struct map_info), GFP_KERNEL);
+		if (!info) {
+			curr = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+		info->next = prev;
+		prev = info;
+	} while (--more);
+
+	goto again;
+ out:
+	while (prev)
+		prev = free_map_info(prev);
+	return curr;
 }
 
 static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 {
-	struct list_head try_list;
-	struct vm_area_struct *vma;
-	struct address_space *mapping;
-	struct vma_info *vi, *tmpvi;
-	struct mm_struct *mm;
-	loff_t vaddr;
-	int ret;
+	struct map_info *info;
+	int err = 0;
 
-	mapping = uprobe->inode->i_mapping;
-	INIT_LIST_HEAD(&try_list);
-
-	ret = 0;
+	info = build_map_info(uprobe->inode->i_mapping,
+					uprobe->offset, is_register);
+	if (IS_ERR(info))
+		return PTR_ERR(info);
 
-	for (;;) {
-		vi = find_next_vma_info(mapping, &try_list, uprobe->offset, is_register);
-		if (!vi)
-			break;
+	while (info) {
+		struct mm_struct *mm = info->mm;
+		struct vm_area_struct *vma;
+		loff_t vaddr;
 
-		if (IS_ERR(vi)) {
-			ret = PTR_ERR(vi);
-			break;
-		}
+		if (err)
+			goto free;
 
-		mm = vi->mm;
 		down_write(&mm->mmap_sem);
-		vma = find_vma(mm, (unsigned long)vi->vaddr);
-		if (!vma || !valid_vma(vma, is_register)) {
-			list_del(&vi->probe_list);
-			kfree(vi);
-			up_write(&mm->mmap_sem);
-			mmput(mm);
-			continue;
-		}
+		vma = find_vma(mm, (unsigned long)info->vaddr);
+		if (!vma || !valid_vma(vma, is_register))
+			goto unlock;
+
 		vaddr = vma_address(vma, uprobe->offset);
 		if (vma->vm_file->f_mapping->host != uprobe->inode ||
-						vaddr != vi->vaddr) {
-			list_del(&vi->probe_list);
-			kfree(vi);
-			up_write(&mm->mmap_sem);
-			mmput(mm);
-			continue;
-		}
+						vaddr != info->vaddr)
+			goto unlock;
 
-		if (is_register)
-			ret = install_breakpoint(uprobe, mm, vma, vi->vaddr);
-		else
-			remove_breakpoint(uprobe, mm, vi->vaddr);
-
-		up_write(&mm->mmap_sem);
-		mmput(mm);
 		if (is_register) {
-			if (ret && ret == -EEXIST)
-				ret = 0;
-			if (ret)
-				break;
+			err = install_breakpoint(uprobe, mm, vma, info->vaddr);
+			if (err == -EEXIST)
+				err = 0;
+		} else {
+			remove_breakpoint(uprobe, mm, info->vaddr);
 		}
+ unlock:
+		up_write(&mm->mmap_sem);
+ free:
+		mmput(mm);
+		info = free_map_info(info);
 	}
 
-	list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
-		list_del(&vi->probe_list);
-		kfree(vi);
-	}
-
-	return ret;
+	return err;
 }
 
 static int __uprobe_register(struct uprobe *uprobe)

index ec78152..4e0db34 100644
@@ -60,17 +60,6 @@ static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
  */
 static atomic_t uprobe_events = ATOMIC_INIT(0);
 
-/*
- * Maintain a temporary per vma info that can be used to search if a vma
- * has already been handled. This structure is introduced since extending
- * vm_area_struct wasnt recommended.
- */
-struct vma_info {
-	struct list_head	probe_list;
-	struct mm_struct	*mm;
-	loff_t			vaddr;
-};
-
 struct uprobe {
 	struct rb_node		rb_node;	/* node in the rb tree */
 	atomic_t		ref;

@@ -742,139 +731,123 @@ static void delete_uprobe(struct uprobe *uprobe)
 	atomic_dec(&uprobe_events);
 }
 
-static struct vma_info *
-__find_next_vma_info(struct address_space *mapping, struct list_head *head,
-			struct vma_info *vi, loff_t offset, bool is_register)
+struct map_info {
+	struct map_info *next;
+	struct mm_struct *mm;
+	loff_t vaddr;
+};
+
+static inline struct map_info *free_map_info(struct map_info *info)
 {
+	struct map_info *next = info->next;
+	kfree(info);
+	return next;
+}
+
+static struct map_info *
+build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
+{
+	unsigned long pgoff = offset >> PAGE_SHIFT;
 	struct prio_tree_iter iter;
 	struct vm_area_struct *vma;
-	struct vma_info *tmpvi;
-	unsigned long pgoff;
-	int existing_vma;
-	loff_t vaddr;
-
-	pgoff = offset >> PAGE_SHIFT;
+	struct map_info *curr = NULL;
+	struct map_info *prev = NULL;
+	struct map_info *info;
+	int more = 0;
 
+ again:
+	mutex_lock(&mapping->i_mmap_mutex);
 	vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
 		if (!valid_vma(vma, is_register))
 			continue;
 
-		existing_vma = 0;
-		vaddr = vma_address(vma, offset);
-
-		list_for_each_entry(tmpvi, head, probe_list) {
-			if (tmpvi->mm == vma->vm_mm && tmpvi->vaddr == vaddr) {
-				existing_vma = 1;
-				break;
-			}
-		}
-
-		/*
-		 * Another vma needs a probe to be installed. However skip
-		 * installing the probe if the vma is about to be unlinked.
-		 */
-		if (!existing_vma && atomic_inc_not_zero(&vma->vm_mm->mm_users)) {
-			vi->mm = vma->vm_mm;
-			vi->vaddr = vaddr;
-			list_add(&vi->probe_list, head);
-
-			return vi;
+		if (!prev) {
+			more++;
+			continue;
 		}
-	}
-
-	return NULL;
-}
 
-/*
- * Iterate in the rmap prio tree  and find a vma where a probe has not
- * yet been inserted.
- */
-static struct vma_info *
-find_next_vma_info(struct address_space *mapping, struct list_head *head,
-		loff_t offset, bool is_register)
-{
-	struct vma_info *vi, *retvi;
+		if (!atomic_inc_not_zero(&vma->vm_mm->mm_users))
+			continue;
 
-	vi = kzalloc(sizeof(struct vma_info), GFP_KERNEL);
-	if (!vi)
-		return ERR_PTR(-ENOMEM);
+		info = prev;
+		prev = prev->next;
+		info->next = curr;
+		curr = info;
 
-	mutex_lock(&mapping->i_mmap_mutex);
-	retvi = __find_next_vma_info(mapping, head, vi, offset, is_register);
+		info->mm = vma->vm_mm;
+		info->vaddr = vma_address(vma, offset);
+	}
 	mutex_unlock(&mapping->i_mmap_mutex);
 
-	if (!retvi)
-		kfree(vi);
+	if (!more)
+		goto out;
+
+	prev = curr;
+	while (curr) {
+		mmput(curr->mm);
+		curr = curr->next;
+	}
 
-	return retvi;
+	do {
+		info = kmalloc(sizeof(struct map_info), GFP_KERNEL);
+		if (!info) {
+			curr = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+		info->next = prev;
+		prev = info;
+	} while (--more);
+
+	goto again;
+ out:
+	while (prev)
+		prev = free_map_info(prev);
+	return curr;
 }
 
 static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 {
-	struct list_head try_list;
-	struct vm_area_struct *vma;
-	struct address_space *mapping;
-	struct vma_info *vi, *tmpvi;
-	struct mm_struct *mm;
-	loff_t vaddr;
-	int ret;
+	struct map_info *info;
+	int err = 0;
 
-	mapping = uprobe->inode->i_mapping;
-	INIT_LIST_HEAD(&try_list);
-
-	ret = 0;
+	info = build_map_info(uprobe->inode->i_mapping,
+					uprobe->offset, is_register);
+	if (IS_ERR(info))
+		return PTR_ERR(info);
 
-	for (;;) {
-		vi = find_next_vma_info(mapping, &try_list, uprobe->offset, is_register);
-		if (!vi)
-			break;
+	while (info) {
+		struct mm_struct *mm = info->mm;
+		struct vm_area_struct *vma;
+		loff_t vaddr;
 
-		if (IS_ERR(vi)) {
-			ret = PTR_ERR(vi);
-			break;
-		}
+		if (err)
+			goto free;
 
-		mm = vi->mm;
 		down_write(&mm->mmap_sem);
-		vma = find_vma(mm, (unsigned long)vi->vaddr);
-		if (!vma || !valid_vma(vma, is_register)) {
-			list_del(&vi->probe_list);
-			kfree(vi);
-			up_write(&mm->mmap_sem);
-			mmput(mm);
-			continue;
-		}
+		vma = find_vma(mm, (unsigned long)info->vaddr);
+		if (!vma || !valid_vma(vma, is_register))
+			goto unlock;
+
 		vaddr = vma_address(vma, uprobe->offset);
 		if (vma->vm_file->f_mapping->host != uprobe->inode ||
-						vaddr != vi->vaddr) {
-			list_del(&vi->probe_list);
-			kfree(vi);
-			up_write(&mm->mmap_sem);
-			mmput(mm);
-			continue;
-		}
+						vaddr != info->vaddr)
+			goto unlock;
 
-		if (is_register)
-			ret = install_breakpoint(uprobe, mm, vma, vi->vaddr);
-		else
-			remove_breakpoint(uprobe, mm, vi->vaddr);
-
-		up_write(&mm->mmap_sem);
-		mmput(mm);
 		if (is_register) {
-			if (ret && ret == -EEXIST)
-				ret = 0;
-			if (ret)
-				break;
+			err = install_breakpoint(uprobe, mm, vma, info->vaddr);
+			if (err == -EEXIST)
+				err = 0;
+		} else {
+			remove_breakpoint(uprobe, mm, info->vaddr);
 		}
+ unlock:
+		up_write(&mm->mmap_sem);
+ free:
+		mmput(mm);
+		info = free_map_info(info);
 	}
 
-	list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
-		list_del(&vi->probe_list);
-		kfree(vi);
-	}
-
-	return ret;
+	return err;
 }
 
 static int __uprobe_register(struct uprobe *uprobe)

index 4e0db34..897417d 100644
@@ -761,6 +761,16 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
 		if (!valid_vma(vma, is_register))
 			continue;
 
+		if (!prev && !more) {
+			/*
+			 * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through
+			 * reclaim. This is optimistic, no harm done if it fails.
+			 */
+			prev = kmalloc(sizeof(struct map_info),
+					GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
+			if (prev)
+				prev->next = NULL;
+		}
 		if (!prev) {
 			more++;
 			continue;

index 4e0db34..897417d 100644
@@ -761,6 +761,16 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
 		if (!valid_vma(vma, is_register))
 			continue;
 
+		if (!prev && !more) {
+			/*
+			 * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through
+			 * reclaim. This is optimistic, no harm done if it fails.
+			 */
+			prev = kmalloc(sizeof(struct map_info),
+					GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
+			if (prev)
+				prev->next = NULL;
+		}
 		if (!prev) {
 			more++;
 			continue;

index 897417d..2671d9a 100644
@@ -44,6 +44,23 @@ static DEFINE_SPINLOCK(uprobes_treelock);	/* serialize rbtree access */
 
 #define UPROBES_HASH_SZ	13
 
+/*
+ * We need separate register/unregister and mmap/munmap lock hashes because
+ * of mmap_sem nesting.
+ *
+ * uprobe_register() needs to install probes on (potentially) all processes
+ * and thus needs to acquire multiple mmap_sems (consequtively, not
+ * concurrently), whereas uprobe_mmap() is called while holding mmap_sem
+ * for the particular process doing the mmap.
+ *
+ * uprobe_register()->register_for_each_vma() needs to drop/acquire mmap_sem
+ * because of lock order against i_mmap_mutex. This means there's a hole in
+ * the register vma iteration where a mmap() can happen.
+ *
+ * Thus uprobe_register() can race with uprobe_mmap() and we can try and
+ * install a probe where one is already installed.
+ */
+
 /* serialize (un)register */
 static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
 

@@ -339,7 +356,9 @@ out:
 int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
 {
 	int result;
-
+	/*
+	 * See the comment near uprobes_hash().
+	 */
 	result = is_swbp_at_addr(mm, vaddr);
 	if (result == 1)
 		return -EEXIST;

@@ -845,6 +864,10 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 
 		if (is_register) {
 			err = install_breakpoint(uprobe, mm, vma, info->vaddr);
+			/*
+			 * We can race against uprobe_mmap(), see the
+			 * comment near uprobe_hash().
+			 */
 			if (err == -EEXIST)
 				err = 0;
 		} else {

@@ -1054,8 +1077,10 @@ int uprobe_mmap(struct vm_area_struct *vma)
 			}
 
 			ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
-
-			/* Ignore double add: */
+			/*
+			 * We can race against uprobe_register(), see the
+			 * comment near uprobe_hash().
+			 */
 			if (ret == -EEXIST) {
 				ret = 0;
 

index 897417d..2671d9a 100644
@@ -44,6 +44,23 @@ static DEFINE_SPINLOCK(uprobes_treelock);	/* serialize rbtree access */
 
 #define UPROBES_HASH_SZ	13
 
+/*
+ * We need separate register/unregister and mmap/munmap lock hashes because
+ * of mmap_sem nesting.
+ *
+ * uprobe_register() needs to install probes on (potentially) all processes
+ * and thus needs to acquire multiple mmap_sems (consequtively, not
+ * concurrently), whereas uprobe_mmap() is called while holding mmap_sem
+ * for the particular process doing the mmap.
+ *
+ * uprobe_register()->register_for_each_vma() needs to drop/acquire mmap_sem
+ * because of lock order against i_mmap_mutex. This means there's a hole in
+ * the register vma iteration where a mmap() can happen.
+ *
+ * Thus uprobe_register() can race with uprobe_mmap() and we can try and
+ * install a probe where one is already installed.
+ */
+
 /* serialize (un)register */
 static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
 

@@ -339,7 +356,9 @@ out:
 int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
 {
 	int result;
-
+	/*
+	 * See the comment near uprobes_hash().
+	 */
 	result = is_swbp_at_addr(mm, vaddr);
 	if (result == 1)
 		return -EEXIST;

@@ -845,6 +864,10 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 
 		if (is_register) {
 			err = install_breakpoint(uprobe, mm, vma, info->vaddr);
+			/*
+			 * We can race against uprobe_mmap(), see the
+			 * comment near uprobe_hash().
+			 */
 			if (err == -EEXIST)
 				err = 0;
 		} else {

@@ -1054,8 +1077,10 @@ int uprobe_mmap(struct vm_area_struct *vma)
 			}
 
 			ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
-
-			/* Ignore double add: */
+			/*
+			 * We can race against uprobe_register(), see the
+			 * comment near uprobe_hash().
+			 */
 			if (ret == -EEXIST) {
 				ret = 0;
 

index 2671d9a..08ef566 100644
@@ -591,10 +591,9 @@ static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc)
 }
 
 static int
-__copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *insn,
+__copy_insn(struct address_space *mapping, struct file *filp, char *insn,
 			unsigned long nbytes, unsigned long offset)
 {
-	struct file *filp = vma->vm_file;
 	struct page *page;
 	void *vaddr;
 	unsigned long off1;

@@ -625,15 +624,13 @@ __copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *ins
 	return 0;
 }
 
-static int
-copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
+static int copy_insn(struct uprobe *uprobe, struct file *filp)
 {
 	struct address_space *mapping;
 	unsigned long nbytes;
 	int bytes;
 
-	addr &= ~PAGE_MASK;
-	nbytes = PAGE_SIZE - addr;
+	nbytes = PAGE_SIZE - (uprobe->offset & ~PAGE_MASK);
 	mapping = uprobe->inode->i_mapping;
 
 	/* Instruction at end of binary; copy only available bytes */

@@ -644,13 +641,13 @@ copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
 
 	/* Instruction at the page-boundary; copy bytes in second page */
 	if (nbytes < bytes) {
-		if (__copy_insn(mapping, vma, uprobe->arch.insn + nbytes,
+		if (__copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
 				bytes - nbytes, uprobe->offset + nbytes))
 			return -ENOMEM;
 
 		bytes = nbytes;
 	}
-	return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset);
+	return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset);
 }
 
 /*

@@ -696,7 +693,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 	addr = (unsigned long)vaddr;
 
 	if (!(uprobe->flags & UPROBE_COPY_INSN)) {
-		ret = copy_insn(uprobe, vma, addr);
+		ret = copy_insn(uprobe, vma->vm_file);
 		if (ret)
 			return ret;
 

index 2671d9a..08ef566 100644
@@ -591,10 +591,9 @@ static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc)
 }
 
 static int
-__copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *insn,
+__copy_insn(struct address_space *mapping, struct file *filp, char *insn,
 			unsigned long nbytes, unsigned long offset)
 {
-	struct file *filp = vma->vm_file;
 	struct page *page;
 	void *vaddr;
 	unsigned long off1;

@@ -625,15 +624,13 @@ __copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *ins
 	return 0;
 }
 
-static int
-copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
+static int copy_insn(struct uprobe *uprobe, struct file *filp)
 {
 	struct address_space *mapping;
 	unsigned long nbytes;
 	int bytes;
 
-	addr &= ~PAGE_MASK;
-	nbytes = PAGE_SIZE - addr;
+	nbytes = PAGE_SIZE - (uprobe->offset & ~PAGE_MASK);
 	mapping = uprobe->inode->i_mapping;
 
 	/* Instruction at end of binary; copy only available bytes */

@@ -644,13 +641,13 @@ copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
 
 	/* Instruction at the page-boundary; copy bytes in second page */
 	if (nbytes < bytes) {
-		if (__copy_insn(mapping, vma, uprobe->arch.insn + nbytes,
+		if (__copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
 				bytes - nbytes, uprobe->offset + nbytes))
 			return -ENOMEM;
 
 		bytes = nbytes;
 	}
-	return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset);
+	return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset);
 }
 
 /*

@@ -696,7 +693,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 	addr = (unsigned long)vaddr;
 
 	if (!(uprobe->flags & UPROBE_COPY_INSN)) {
-		ret = copy_insn(uprobe, vma, addr);
+		ret = copy_insn(uprobe, vma->vm_file);
 		if (ret)
 			return ret;
 

index 08ef566..2db1d94 100644
@@ -641,10 +641,10 @@ static int copy_insn(struct uprobe *uprobe, struct file *filp)
 
 	/* Instruction at the page-boundary; copy bytes in second page */
 	if (nbytes < bytes) {
-		if (__copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
-				bytes - nbytes, uprobe->offset + nbytes))
-			return -ENOMEM;
-
+		int err = __copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
+				bytes - nbytes, uprobe->offset + nbytes);
+		if (err)
+			return err;
 		bytes = nbytes;
 	}
 	return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset);

index 08ef566..2db1d94 100644
@@ -641,10 +641,10 @@ static int copy_insn(struct uprobe *uprobe, struct file *filp)
 
 	/* Instruction at the page-boundary; copy bytes in second page */
 	if (nbytes < bytes) {
-		if (__copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
-				bytes - nbytes, uprobe->offset + nbytes))
-			return -ENOMEM;
-
+		int err = __copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
+				bytes - nbytes, uprobe->offset + nbytes);
+		if (err)
+			return err;
 		bytes = nbytes;
 	}
 	return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset);

index 2db1d94..14c71a2 100644
@@ -211,7 +211,6 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	struct vm_area_struct *vma;
 	struct uprobe *uprobe;
 	unsigned long pgoff;
-	loff_t addr;
 	int ret;
 retry:
 	/* Read the page with vaddr into memory */

@@ -235,10 +234,6 @@ retry:
 	if (mapping != vma->vm_file->f_mapping)
 		goto put_out;
 
-	addr = vma_address(vma, uprobe->offset);
-	if (vaddr != (unsigned long)addr)
-		goto put_out;
-
 	ret = -ENOMEM;
 	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
 	if (!new_page)

index 2db1d94..14c71a2 100644
@@ -211,7 +211,6 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	struct vm_area_struct *vma;
 	struct uprobe *uprobe;
 	unsigned long pgoff;
-	loff_t addr;
 	int ret;
 retry:
 	/* Read the page with vaddr into memory */

@@ -235,10 +234,6 @@ retry:
 	if (mapping != vma->vm_file->f_mapping)
 		goto put_out;
 
-	addr = vma_address(vma, uprobe->offset);
-	if (vaddr != (unsigned long)addr)
-		goto put_out;
-
 	ret = -ENOMEM;
 	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
 	if (!new_page)

index 14c71a2..b9c61bd 100644
@@ -210,7 +210,6 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	void *vaddr_old, *vaddr_new;
 	struct vm_area_struct *vma;
 	struct uprobe *uprobe;
-	unsigned long pgoff;
 	int ret;
 retry:
 	/* Read the page with vaddr into memory */

@@ -251,11 +250,7 @@ retry:
 	vaddr_new = kmap_atomic(new_page);
 
 	memcpy(vaddr_new, vaddr_old, PAGE_SIZE);
-
-	/* poke the new insn in, ASSUMES we don't cross page boundary */
-	pgoff = (vaddr & ~PAGE_MASK);
-	BUG_ON(pgoff + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
-	memcpy(vaddr_new + pgoff, &opcode, UPROBE_SWBP_INSN_SIZE);
+	memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE);
 
 	kunmap_atomic(vaddr_new);
 	kunmap_atomic(vaddr_old);

@@ -699,6 +694,10 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 		if (ret)
 			return ret;
 
+		/* write_opcode() assumes we don't cross page boundary */
+		BUG_ON((uprobe->offset & ~PAGE_MASK) +
+				UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
+
 		uprobe->flags |= UPROBE_COPY_INSN;
 	}
 

index 14c71a2..b9c61bd 100644
@@ -210,7 +210,6 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	void *vaddr_old, *vaddr_new;
 	struct vm_area_struct *vma;
 	struct uprobe *uprobe;
-	unsigned long pgoff;
 	int ret;
 retry:
 	/* Read the page with vaddr into memory */

@@ -251,11 +250,7 @@ retry:
 	vaddr_new = kmap_atomic(new_page);
 
 	memcpy(vaddr_new, vaddr_old, PAGE_SIZE);
-
-	/* poke the new insn in, ASSUMES we don't cross page boundary */
-	pgoff = (vaddr & ~PAGE_MASK);
-	BUG_ON(pgoff + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
-	memcpy(vaddr_new + pgoff, &opcode, UPROBE_SWBP_INSN_SIZE);
+	memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE);
 
 	kunmap_atomic(vaddr_new);
 	kunmap_atomic(vaddr_old);

@@ -699,6 +694,10 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 		if (ret)
 			return ret;
 
+		/* write_opcode() assumes we don't cross page boundary */
+		BUG_ON((uprobe->offset & ~PAGE_MASK) +
+				UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
+
 		uprobe->flags |= UPROBE_COPY_INSN;
 	}
 

index b9c61bd..7d5c78f 100644
@@ -513,7 +513,6 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
 	uprobe->inode = igrab(inode);
 	uprobe->offset = offset;
 	init_rwsem(&uprobe->consumer_rwsem);
-	INIT_LIST_HEAD(&uprobe->pending_list);
 
 	/* add to uprobes_tree, sorted on inode:offset */
 	cur_uprobe = insert_uprobe(uprobe);

@@ -1037,7 +1036,7 @@ static void build_probe_list(struct inode *inode, struct list_head *head)
 int uprobe_mmap(struct vm_area_struct *vma)
 {
 	struct list_head tmp_list;
-	struct uprobe *uprobe, *u;
+	struct uprobe *uprobe;
 	struct inode *inode;
 	int ret, count;
 

@@ -1055,10 +1054,9 @@ int uprobe_mmap(struct vm_area_struct *vma)
 	ret = 0;
 	count = 0;
 
-	list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
+	list_for_each_entry(uprobe, &tmp_list, pending_list) {
 		loff_t vaddr;
 
-		list_del(&uprobe->pending_list);
 		if (!ret) {
 			vaddr = vma_address(vma, uprobe->offset);
 

@@ -1106,7 +1104,7 @@ int uprobe_mmap(struct vm_area_struct *vma)
 void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
 {
 	struct list_head tmp_list;
-	struct uprobe *uprobe, *u;
+	struct uprobe *uprobe;
 	struct inode *inode;
 
 	if (!atomic_read(&uprobe_events) || !valid_vma(vma, false))

@@ -1123,12 +1121,10 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
 	mutex_lock(uprobes_mmap_hash(inode));
 	build_probe_list(inode, &tmp_list);
 
-	list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
+	list_for_each_entry(uprobe, &tmp_list, pending_list) {
 		loff_t vaddr;
 
-		list_del(&uprobe->pending_list);
 		vaddr = vma_address(vma, uprobe->offset);
-
 		if (vaddr >= start && vaddr < end) {
 			/*
 			 * An unregister could have removed the probe before

index b9c61bd..7d5c78f 100644
@@ -513,7 +513,6 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
 	uprobe->inode = igrab(inode);
 	uprobe->offset = offset;
 	init_rwsem(&uprobe->consumer_rwsem);
-	INIT_LIST_HEAD(&uprobe->pending_list);
 
 	/* add to uprobes_tree, sorted on inode:offset */
 	cur_uprobe = insert_uprobe(uprobe);

@@ -1037,7 +1036,7 @@ static void build_probe_list(struct inode *inode, struct list_head *head)
 int uprobe_mmap(struct vm_area_struct *vma)
 {
 	struct list_head tmp_list;
-	struct uprobe *uprobe, *u;
+	struct uprobe *uprobe;
 	struct inode *inode;
 	int ret, count;
 

@@ -1055,10 +1054,9 @@ int uprobe_mmap(struct vm_area_struct *vma)
 	ret = 0;
 	count = 0;
 
-	list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
+	list_for_each_entry(uprobe, &tmp_list, pending_list) {
 		loff_t vaddr;
 
-		list_del(&uprobe->pending_list);
 		if (!ret) {
 			vaddr = vma_address(vma, uprobe->offset);
 

@@ -1106,7 +1104,7 @@ int uprobe_mmap(struct vm_area_struct *vma)
 void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
 {
 	struct list_head tmp_list;
-	struct uprobe *uprobe, *u;
+	struct uprobe *uprobe;
 	struct inode *inode;
 
 	if (!atomic_read(&uprobe_events) || !valid_vma(vma, false))

@@ -1123,12 +1121,10 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
 	mutex_lock(uprobes_mmap_hash(inode));
 	build_probe_list(inode, &tmp_list);
 
-	list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
+	list_for_each_entry(uprobe, &tmp_list, pending_list) {
 		loff_t vaddr;
 
-		list_del(&uprobe->pending_list);
 		vaddr = vma_address(vma, uprobe->offset);
-
 		if (vaddr >= start && vaddr < end) {
 			/*
 			 * An unregister could have removed the probe before

index 7d5c78f..4df84b7 100644
@@ -664,9 +664,8 @@ static int copy_insn(struct uprobe *uprobe, struct file *filp)
  */
 static int
 install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
-			struct vm_area_struct *vma, loff_t vaddr)
+			struct vm_area_struct *vma, unsigned long vaddr)
 {
-	unsigned long addr;
 	int ret;
 
 	/*

@@ -679,8 +678,6 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 	if (!uprobe->consumers)
 		return -EEXIST;
 
-	addr = (unsigned long)vaddr;
-
 	if (!(uprobe->flags & UPROBE_COPY_INSN)) {
 		ret = copy_insn(uprobe, vma->vm_file);
 		if (ret)

@@ -689,7 +686,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 		if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
 			return -ENOTSUPP;
 
-		ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, addr);
+		ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
 		if (ret)
 			return ret;
 

@@ -709,7 +706,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 	 * Hence increment before and decrement on failure.
 	 */
 	atomic_inc(&mm->uprobes_state.count);
-	ret = set_swbp(&uprobe->arch, mm, addr);
+	ret = set_swbp(&uprobe->arch, mm, vaddr);
 	if (ret)
 		atomic_dec(&mm->uprobes_state.count);
 

@@ -717,9 +714,9 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 }
 
 static void
-remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, loff_t vaddr)
+remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr)
 {
-	if (!set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true))
+	if (!set_orig_insn(&uprobe->arch, mm, vaddr, true))
 		atomic_dec(&mm->uprobes_state.count);
 }
 

@@ -743,7 +740,7 @@ static void delete_uprobe(struct uprobe *uprobe)
 struct map_info {
 	struct map_info *next;
 	struct mm_struct *mm;
-	loff_t vaddr;
+	unsigned long vaddr;
 };
 
 static inline struct map_info *free_map_info(struct map_info *info)

@@ -837,7 +834,6 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 	while (info) {
 		struct mm_struct *mm = info->mm;
 		struct vm_area_struct *vma;
-		loff_t vaddr;
 
 		if (err)
 			goto free;

@@ -847,9 +843,8 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 		if (!vma || !valid_vma(vma, is_register))
 			goto unlock;
 
-		vaddr = vma_address(vma, uprobe->offset);
 		if (vma->vm_file->f_mapping->host != uprobe->inode ||
-						vaddr != info->vaddr)
+		    vma_address(vma, uprobe->offset) != info->vaddr)
 			goto unlock;
 
 		if (is_register) {

@@ -1055,10 +1050,8 @@ int uprobe_mmap(struct vm_area_struct *vma)
 	count = 0;
 
 	list_for_each_entry(uprobe, &tmp_list, pending_list) {
-		loff_t vaddr;
-
 		if (!ret) {
-			vaddr = vma_address(vma, uprobe->offset);
+			loff_t vaddr = vma_address(vma, uprobe->offset);
 
 			if (vaddr < vma->vm_start || vaddr >= vma->vm_end) {
 				put_uprobe(uprobe);

@@ -1122,9 +1115,8 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
 	build_probe_list(inode, &tmp_list);
 
 	list_for_each_entry(uprobe, &tmp_list, pending_list) {
-		loff_t vaddr;
+		loff_t vaddr = vma_address(vma, uprobe->offset);
 
-		vaddr = vma_address(vma, uprobe->offset);
 		if (vaddr >= start && vaddr < end) {
 			/*
 			 * An unregister could have removed the probe before

index 7d5c78f..4df84b7 100644
@@ -664,9 +664,8 @@ static int copy_insn(struct uprobe *uprobe, struct file *filp)
  */
 static int
 install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
-			struct vm_area_struct *vma, loff_t vaddr)
+			struct vm_area_struct *vma, unsigned long vaddr)
 {
-	unsigned long addr;
 	int ret;
 
 	/*

@@ -679,8 +678,6 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 	if (!uprobe->consumers)
 		return -EEXIST;
 
-	addr = (unsigned long)vaddr;
-
 	if (!(uprobe->flags & UPROBE_COPY_INSN)) {
 		ret = copy_insn(uprobe, vma->vm_file);
 		if (ret)

@@ -689,7 +686,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 		if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
 			return -ENOTSUPP;
 
-		ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, addr);
+		ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
 		if (ret)
 			return ret;
 

@@ -709,7 +706,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 	 * Hence increment before and decrement on failure.
 	 */
 	atomic_inc(&mm->uprobes_state.count);
-	ret = set_swbp(&uprobe->arch, mm, addr);
+	ret = set_swbp(&uprobe->arch, mm, vaddr);
 	if (ret)
 		atomic_dec(&mm->uprobes_state.count);
 

@@ -717,9 +714,9 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
 }
 
 static void
-remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, loff_t vaddr)
+remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr)
 {
-	if (!set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true))
+	if (!set_orig_insn(&uprobe->arch, mm, vaddr, true))
 		atomic_dec(&mm->uprobes_state.count);
 }
 

@@ -743,7 +740,7 @@ static void delete_uprobe(struct uprobe *uprobe)
 struct map_info {
 	struct map_info *next;
 	struct mm_struct *mm;
-	loff_t vaddr;
+	unsigned long vaddr;
 };
 
 static inline struct map_info *free_map_info(struct map_info *info)

@@ -837,7 +834,6 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 	while (info) {
 		struct mm_struct *mm = info->mm;
 		struct vm_area_struct *vma;
-		loff_t vaddr;
 
 		if (err)
 			goto free;

@@ -847,9 +843,8 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 		if (!vma || !valid_vma(vma, is_register))
 			goto unlock;
 
-		vaddr = vma_address(vma, uprobe->offset);
 		if (vma->vm_file->f_mapping->host != uprobe->inode ||
-						vaddr != info->vaddr)
+		    vma_address(vma, uprobe->offset) != info->vaddr)
 			goto unlock;
 
 		if (is_register) {

@@ -1055,10 +1050,8 @@ int uprobe_mmap(struct vm_area_struct *vma)
 	count = 0;
 
 	list_for_each_entry(uprobe, &tmp_list, pending_list) {
-		loff_t vaddr;
-
 		if (!ret) {
-			vaddr = vma_address(vma, uprobe->offset);
+			loff_t vaddr = vma_address(vma, uprobe->offset);
 
 			if (vaddr < vma->vm_start || vaddr >= vma->vm_end) {
 				put_uprobe(uprobe);

@@ -1122,9 +1115,8 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
 	build_probe_list(inode, &tmp_list);
 
 	list_for_each_entry(uprobe, &tmp_list, pending_list) {
-		loff_t vaddr;
+		loff_t vaddr = vma_address(vma, uprobe->offset);
 
-		vaddr = vma_address(vma, uprobe->offset);
 		if (vaddr >= start && vaddr < end) {
 			/*
 			 * An unregister could have removed the probe before

index 4df84b7..d1b2eeb 100644
@@ -581,12 +581,12 @@ static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc)
 
 static int
 __copy_insn(struct address_space *mapping, struct file *filp, char *insn,
-			unsigned long nbytes, unsigned long offset)
+			unsigned long nbytes, loff_t offset)
 {
 	struct page *page;
 	void *vaddr;
-	unsigned long off1;
-	unsigned long idx;
+	unsigned long off;
+	pgoff_t idx;
 
 	if (!filp)
 		return -EINVAL;

@@ -594,8 +594,8 @@ __copy_insn(struct address_space *mapping, struct file *filp, char *insn,
 	if (!mapping->a_ops->readpage)
 		return -EIO;
 
-	idx = (unsigned long)(offset >> PAGE_CACHE_SHIFT);
-	off1 = offset &= ~PAGE_MASK;
+	idx = offset >> PAGE_CACHE_SHIFT;
+	off = offset & ~PAGE_MASK;
 
 	/*
 	 * Ensure that the page that has the original instruction is

@@ -606,7 +606,7 @@ __copy_insn(struct address_space *mapping, struct file *filp, char *insn,
 		return PTR_ERR(page);
 
 	vaddr = kmap_atomic(page);
-	memcpy(insn, vaddr + off1, nbytes);
+	memcpy(insn, vaddr + off, nbytes);
 	kunmap_atomic(vaddr);
 	page_cache_release(page);
 

index 4df84b7..d1b2eeb 100644
@@ -581,12 +581,12 @@ static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc)
 
 static int
 __copy_insn(struct address_space *mapping, struct file *filp, char *insn,
-			unsigned long nbytes, unsigned long offset)
+			unsigned long nbytes, loff_t offset)
 {
 	struct page *page;
 	void *vaddr;
-	unsigned long off1;
-	unsigned long idx;
+	unsigned long off;
+	pgoff_t idx;
 
 	if (!filp)
 		return -EINVAL;

@@ -594,8 +594,8 @@ __copy_insn(struct address_space *mapping, struct file *filp, char *insn,
 	if (!mapping->a_ops->readpage)
 		return -EIO;
 
-	idx = (unsigned long)(offset >> PAGE_CACHE_SHIFT);
-	off1 = offset &= ~PAGE_MASK;
+	idx = offset >> PAGE_CACHE_SHIFT;
+	off = offset & ~PAGE_MASK;
 
 	/*
 	 * Ensure that the page that has the original instruction is

@@ -606,7 +606,7 @@ __copy_insn(struct address_space *mapping, struct file *filp, char *insn,
 		return PTR_ERR(page);
 
 	vaddr = kmap_atomic(page);
-	memcpy(insn, vaddr + off1, nbytes);
+	memcpy(insn, vaddr + off, nbytes);
 	kunmap_atomic(vaddr);
 	page_cache_release(page);
 

index d1b2eeb..f935327 100644
@@ -1392,7 +1392,6 @@ static struct uprobe_task *add_utask(void)
 	if (unlikely(!utask))
 		return NULL;
 
-	utask->active_uprobe = NULL;
 	current->utask = utask;
 	return utask;
 }

index d1b2eeb..f935327 100644
@@ -1392,7 +1392,6 @@ static struct uprobe_task *add_utask(void)
 	if (unlikely(!utask))
 		return NULL;
 
-	utask->active_uprobe = NULL;
 	current->utask = utask;
 	return utask;
 }