On Mon, Aug 25, 2014 at 11:08 AM, Oleg Nesterov <o...@redhat.com> wrote:
>
> 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 <o...@redhat.com>
> Cc: sta...@vger.kernel.org
> ---
> arch/x86/kernel/xsave.c | 5 ++++-
> 1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
> index 453343c..c52eb9c 100644
> --- a/arch/x86/kernel/xsave.c
> +++ b/arch/x86/kernel/xsave.c
> @@ -397,8 +397,11 @@ 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 {
>
oops. looks good to me.
Reviewed-by: Suresh Siddha <sbsid...@gmail.com>
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