Merge 50f09a3dd587 ("Merge tag 'char-misc-5.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc") into char-misc-next

We want the char/misc driver fixes in here as well

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 15 insertions, 19 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index a08cedefbfaa..5d46611cba8d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2258,25 +2258,11 @@ out_nomem:
 static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct shmem_inode_info *info = SHMEM_I(file_inode(file));
+	int ret;
 
-	if (info->seals & F_SEAL_FUTURE_WRITE) {
-		/*
-		 * New PROT_WRITE and MAP_SHARED mmaps are not allowed when
-		 * "future write" seal active.
-		 */
-		if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
-			return -EPERM;
-
-		/*
-		 * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as
-		 * MAP_SHARED and read-only, take care to not allow mprotect to
-		 * revert protections on such mappings. Do this only for shared
-		 * mappings. For private mappings, don't need to mask
-		 * VM_MAYWRITE as we still want them to be COW-writable.
-		 */
-		if (vma->vm_flags & VM_SHARED)
-			vma->vm_flags &= ~(VM_MAYWRITE);
-	}
+	ret = seal_check_future_write(info->seals, vma);
+	if (ret)
+		return ret;
 
 	/* arm64 - allow memory tagging on RAM-based files */
 	vma->vm_flags |= VM_MTE_ALLOWED;
@@ -2375,8 +2361,18 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
 	pgoff_t offset, max_off;
 
 	ret = -ENOMEM;
-	if (!shmem_inode_acct_block(inode, 1))
+	if (!shmem_inode_acct_block(inode, 1)) {
+		/*
+		 * We may have got a page, returned -ENOENT triggering a retry,
+		 * and now we find ourselves with -ENOMEM. Release the page, to
+		 * avoid a BUG_ON in our caller.
+		 */
+		if (unlikely(*pagep)) {
+			put_page(*pagep);
+			*pagep = NULL;
+		}
 		goto out;
+	}
 
 	if (!*pagep) {
 		page = shmem_alloc_page(gfp, info, pgoff);