Re: [PATCH V3] rxe: Fix a sleep-in-atomic bug in post_one_send

[Jia-Ju Bai <baijiaju1990-9Onoh4P/yGk@public.gmane.org>]

On 06/05/2017 04:30 PM, Moni Shoua wrote:
>> -                       if (qp->is_user&&  copy_from_user(p, (__user void *)
>> -                                           (uintptr_t)sge->addr, sge->length))
>> +                       spin_unlock_irqrestore(&qp->sq.sq_lock, *flags);
>> +                       err = copy_from_user(p, (__user void *)
>> +                                       (uintptr_t)sge->addr, sge->length);
>> +                       spin_lock_irqsave(&qp->sq.sq_lock, *flags);
>> +                       if (qp->is_user&&  err)
>>                                  return -EFAULT;
> qp-_is_user is always false in this function (flow starts from
> rxe_post_send_kernel) so this line is a dead code
> In fact, this patch seems to add a serious bug when it uses
> copy_from_user() from a non user pointer.
> Do you agree?
I agree.
So, it is fine to me to remove this line, as you said in the former email:

>  Second, I think that there is no flow that leads to this function
>  when qp->is user is true so maybe the correct action is to remove this
>  line completely
>  if (qp->is_user&&  copy_from_user(p, (__user void *)



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