mm: shmem_zero_setup skip security check and lockdep conflict with XFS

[karo-tx-linux.git] / mm / shmem.c

diff --git a/mm/shmem.c b/mm/shmem.c
index de981370fbc5d596de3d419062c0977829602af7..47d536e59fc02c2251c36ce4d16d654921101cbf 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3401,7 +3401,13 @@ int shmem_zero_setup(struct vm_area_struct *vma)
        struct file *file;
        loff_t size = vma->vm_end - vma->vm_start;
 
-       file = shmem_file_setup("dev/zero", size, vma->vm_flags);
+       /*
+        * Cloning a new file under mmap_sem leads to a lock ordering conflict
+        * between XFS directory reading and selinux: since this file is only
+        * accessible to the user through its mapping, use S_PRIVATE flag to
+        * bypass file security, in the same way as shmem_kernel_file_setup().
+        */
+       file = __shmem_file_setup("dev/zero", size, vma->vm_flags, S_PRIVATE);
        if (IS_ERR(file))
                return PTR_ERR(file);