[ Upstream commit 49e91e70 ]

With this fix, all code paths should now be obtaining the page lock before
f->sem.
Reported-by: Szabó Tamás <sztomi89@gmail.com>
Tested-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>