• Al Viro's avatar
    root dentries need RCU-delayed freeing · abfc0ec6
    Al Viro authored
    commit 90bad5e0 upstream.
    
    Since mountpoint crossing can happen without leaving lazy mode,
    root dentries do need the same protection against having their
    memory freed without RCU delay as everything else in the tree.
    
    It's partially hidden by RCU delay between detaching from the
    mount tree and dropping the vfsmount reference, but the starting
    point of pathwalk can be on an already detached mount, in which
    case umount-caused RCU delay has already passed by the time the
    lazy pathwalk grabs rcu_read_lock().  If the starting point
    happens to be at the root of that vfsmount *and* that vfsmount
    covers the entire filesystem, we get trouble.
    
    Fixes: 48a066e7 ("RCU'd vsfmounts")
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    abfc0ec6
dcache.c 95.6 KB