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Diffstat (limited to 'fs')
-rw-r--r--fs/namespace.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 0a9e766b4087..7ca287c9080a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1599,8 +1599,13 @@ static int do_umount(struct mount *mnt, int flags)
namespace_lock();
lock_mount_hash();
- event++;
+ /* Recheck MNT_LOCKED with the locks held */
+ retval = -EINVAL;
+ if (mnt->mnt.mnt_flags & MNT_LOCKED)
+ goto out;
+
+ event++;
if (flags & MNT_DETACH) {
if (!list_empty(&mnt->mnt_list))
umount_tree(mnt, UMOUNT_PROPAGATE);
@@ -1614,6 +1619,7 @@ static int do_umount(struct mount *mnt, int flags)
retval = 0;
}
}
+out:
unlock_mount_hash();
namespace_unlock();
return retval;
@@ -1704,7 +1710,7 @@ SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
goto dput_and_out;
if (!check_mnt(mnt))
goto dput_and_out;
- if (mnt->mnt.mnt_flags & MNT_LOCKED)
+ if (mnt->mnt.mnt_flags & MNT_LOCKED) /* Check optimistically */
goto dput_and_out;
retval = -EPERM;
if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))