!1115 userswap bugfix

Merge Pull Request from: @ci-robot 
 
PR sync from:  Peng Zhang <zhangpeng362@huawei.com>
 https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/thread/GRJWIT22G2QJFYJL64FIBD6E7V5TTDY5/ 
From: ZhangPeng <zhangpeng362@huawei.com>

Fix Fuzz test BUG_ON and failure to swap out large memory. Two userswap
bugfixes synchronized from hulk5.10.

ZhangPeng (2):
  userswap: fix BUG_ON in userfaultfd_release()
  userswap: fix kmalloc ENOMEM failed for a large memory


-- 
2.25.1
 
 
Link:https://gitee.com/openeuler/kernel/pulls/1115 

Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> 

fs/userfaultfd.c

@@ -873,12 +873,12 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
 	prev = NULL;
 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
 		userfault_flags = VM_UFFD_MISSING | VM_UFFD_WP;
-#ifdef CONFIG_USERSWAP
-		uswap_release(&userfault_flags);
-#endif
 		cond_resched();
 		BUG_ON(!!vma->vm_userfaultfd_ctx.ctx ^
 		       !!(vma->vm_flags & userfault_flags));
+#ifdef CONFIG_USERSWAP
+		uswap_release(&userfault_flags);
+#endif
 		if (vma->vm_userfaultfd_ctx.ctx != ctx) {
 			prev = vma;
 			continue;

mm/userswap.c

@@ -86,7 +86,7 @@ static unsigned long pages_can_be_swapped(struct mm_struct *mm,
 	*ppages = NULL;
 
 
-	pages = kmalloc(sizeof(struct page *) * (len / PAGE_SIZE), GFP_KERNEL);
+	pages = kvzalloc(sizeof(struct page *) * (len / PAGE_SIZE), GFP_KERNEL);
 	if (!pages)
 		return -ENOMEM;
 
@@ -153,7 +153,7 @@ static unsigned long pages_can_be_swapped(struct mm_struct *mm,
 out_err:
 	for (i = 0; i < page_num; i++)
 		put_page(pages[i]);
-	kfree(pages);
+	kvfree(pages);
 	return ret;
 }
 
@@ -299,10 +299,9 @@ static unsigned long do_user_swap(struct mm_struct *mm,
 	unsigned long i = 0, j;
 	int ret;
 
-	ptes = kmalloc(sizeof(pte_t) * (len / PAGE_SIZE), GFP_KERNEL);
+	ptes = kvzalloc(sizeof(pte_t) * (len / PAGE_SIZE), GFP_KERNEL);
 	if (!ptes)
 		return -ENOMEM;
-	memset(ptes, 0, sizeof(pte_t) * (len / PAGE_SIZE));
 	lru_add_drain();
 	for (j = 0; j < len; j += PAGE_SIZE) {
 		page = pages[i];
@@ -350,12 +349,12 @@ static unsigned long do_user_swap(struct mm_struct *mm,
 
 	if (pages_dirty)
 		new_addr_start = new_addr_start | USWAP_PAGES_DIRTY;
-	kfree(ptes);
+	kvfree(ptes);
 	return new_addr_start;
 
 out_recover:
 	uswapout_recover(mm, old_addr_start, i, pages, new_addr_start, ptes);
-	kfree(ptes);
+	kvfree(ptes);
 	return ret;
 }
 
@@ -401,7 +400,7 @@ unsigned long uswap_mremap(unsigned long old_addr, unsigned long old_len,
 	for (i = 0; i < len / PAGE_SIZE; i++)
 		if (pages[i])
 			put_page(pages[i]);
-	kfree(pages);
+	kvfree(pages);
 	return ret;
 }