Re: [PATCH v2 21/29] nios2: Futex operations

Thomas Gleixner
2014-07-15T10:03:35Z

On Tue, 15 Jul 2014, Ley Foon Tan wrote:
+static inline int atomic_futex_op_xchg_set(int oparg, u32 __user *uaddr,
> + int *oldval)
> +{
> + unsigned long flags;
> + int ret;
> +
> + local_irq_save(flags);
> +
> + ret = get_user(*oldval, uaddr);
> + if (!ret)
> + ret = put_user(oparg, uaddr);

This is wrong as it gets. get_user() might fault and sleep.

You need a proper implementation, which handles fault exceptions.

Thanks,

tglx