On 11/28/2017 2:38 PM, Don Dutile wrote:
> On 11/27/2017 06:28 PM, Don Dutile wrote:
>> On 11/27/2017 05:58 PM, Daniel Jurgens wrote:
>>> On 11/27/2017 4:03 PM, Don Dutile wrote:
>>>> On 11/27/2017 06:25 AM, Leon Romanovsky wrote:
>>>>> From: Daniel Jurgens <danielj@xxxxxxxxxxxx>
>>>>>
>>>>>
>>>>> - if (pps_change && !special_qp) {
>>>>> + if (pps_change && !special_qp && real_qp->qp_sec) {
>>>>> mutex_lock(&real_qp->qp_sec->mutex);
>>>>> new_pps = get_new_pps(real_qp,
>>>>> qp_attr,
>>>>> @@ -600,7 +627,7 @@ int ib_security_modify_qp(struct ib_qp *qp,
>>>>> qp_attr_mask,
>>>>> udata);
>>>>>
>>>>> - if (pps_change && !special_qp) {
>>>>> + if (pps_change && !special_qp && real_qp->qp_sec) {
>>>>> /* Clean up the lists and free the appropriate
>>>>> * ports_pkeys structure.
>>>>> */
>>>>>
>>>> This patch breaks the kernel build on RHEL b/c it generates
>>>> a warning in the second if (pps_change && !special_qp && real_qp->qp_sec) {}
>>>> that new_pps may not be assigned. ... build warnings in RHEL kernel == build failure (on x86).
>>>>
>>>> That's b/c the patch adds real_qp->qp_sec to if's conditions,
>>>> and the compiler cannot determine if real_qp->qp_sec cannot be modified
>>>> between the first check like it, above, which sets the value of new_pps,
>>>> and the second check that uses it, because real_qp is passed into the device->modify()
>>>> function call btwn those two if() check's.
>>>>
>>>> The code needs to do something like this in the first if-check:
>>>> .....
>>>> bool new_pps_gotten = false;
>>>> ....
>>>>
>>>> if (pps_change && !special_qp && real_qp->qp_sec) {
>>>> mutex_lock(&real_qp->qp_sec->mutex);
>>>> new_pps = get_new_pps(real_qp,
>>>> qp_attr,
>>>> qp_attr_mask);
>>>> new_pps_gotten = true;
>>>> ....
>>>> }
>>>> ....
>>>>
>>>> and change the second if check to be:
>>>>
>>>> if (new_pps_gotten) {
>>>> * Clean up the lists and free the appropriate
>>>> .....
>>>>
>>>
>>> Thanks Don, I think it's better to initialize new_pps to NULL, vs introducing a new variable. Also, there needs to be a check of new_pps after getting it.
>>>
>> yup, I considered that as well.
>> wasn't sure if lockdep checking code would not like the fact that a mutex_lock() could be taken,
>> but if new_pps == NULL after the get call(it may always succeed, but an analyzer may not conclude the same),
>> that the mutex_unlock() wouldn't be called.
>>
>> the double, same-condition if-check with the fcn call in btwn seems like it ought to be
>> restructured differently so the mutex lock/unlock pairs are contained neatly in a single if-clause,
>> and the new_pps alloc & use would be similarly containted.
>>
>> -dd
>>
>> -
> Is someone doing a v3? I didn't see an email today w/another patch version.
> ... at least I wasn't directly cc'd on one anyhow... off to check linux-rdma folder...
> nothing there... and I don't find a v3 in Leon's tree either.
>
>
I sent a fix-up patch to Leon, but it seems he didn't get to it today. I'll resend this afternoon.
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