Commit df24fb85 authored Sep 02, 2014 by Oleg Nesterov Committed by H. Peter Anvin Sep 02, 2014

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>

parent 66463db4

arch/x86/kernel/xsave.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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 {

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