x86/fpu: Reset state for all signal restore failures

stable inclusion
from linux-4.19.196
commit 55cfd22f9b5a051fa815d6987825e00aa15427af

--------------------------------

commit efa16550 upstream.

If access_ok() or fpregs_soft_set() fails in __fpu__restore_sig() then the
function just returns but does not clear the FPU state as it does for all
other fatal failures.

Clear the FPU state for these failures as well.

Fixes: 72a671ce ("x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/87mtryyhhz.ffs@nanos.tec.linutronix.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Conflicts:
  arch/x86/kernel/fpu/signal.c
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>