do_add_mount() should sanitize mnt_flags
MNT_WRITE_HOLD shouldn't leak into new vfsmount and neither
should MNT_SHARED (the latter will be set properly, along with
the rest of shared-subtree data structures)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index 779293e..c768f73 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1671,6 +1671,8 @@
{
int err;
+ mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD);
+
down_write(&namespace_sem);
/* Something was mounted here while we slept */
while (d_mountpoint(path->dentry) &&