x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable()

Add preempt_disable() + preempt_enable() around math_state_restore() in
__restore_xstate_sig(). Otherwise __switch_to() after __thread_fpu_begin()
can overwrite fpu->state we are going to restore.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20140902175717.GA21649@redhat.com
Cc: <stable@vger.kernel.org> # v3.7+
Reviewed-by: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Oleg Nesterov 2014-09-02 19:57:17 +02:00 committed by H. Peter Anvin
parent 66463db4fc
commit df24fb859a
1 changed files with 4 additions and 1 deletions

View File

@ -400,8 +400,11 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
set_used_math();
}
if (use_eager_fpu())
if (use_eager_fpu()) {
preempt_disable();
math_state_restore();
preempt_enable();
}
return err;
} else {