Re: [PATCH] Fix: Remove racy Subnet Manager sendonly join checks

[Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>]

On 2/10/2021 4:31 AM, Christoph Lameter wrote:
> On Tue, 9 Feb 2021, Jason Gunthorpe wrote:
> 
>> This one got spam filtered and didn't make it to the list:
>>
>> Received-SPF: SoftFail (hqemgatev14.nvidia.com: domain of
>>          cl@linux.com is inclined to not designate 3.19.106.255 as
>>          permitted sender) identity=mailfrom; client-ip=3.19.106.255;
>>          receiver=hqemgatev14.nvidia.com;
>>          envelope-from="cl@linux.com"; x-sender="cl@linux.com";
>>          x-conformance=spf_only; x-record-type="v=spf1"
>>
>> Also the extra From/Date/Subject ended up in the commit message
> 
> Yes the Linux Foundation guys are not willing to address this issue in any
> way. I may have to give up my linux.com email address.
> 
>> I fixed it all up, applied to for-next
> 
> Thank you.
> 
>> It looks like OPA will also suffer this race (opa_pr_query_possible),
>> maybe it is a little less likely since it will be driven by PR queries
>> not broadcast joins.
>>
>> But the same logic is likely true there, I'd be surprised if OPA
>> fabrics are not running a capable OPA SM at this point.
> 
> There is also another potentially racy check in there for OPA in regards
> to the support of path records?
> 
> static bool ib_sa_opa_pathrecord_support(struct ib_sa_client *client,
>                                           struct ib_sa_device *sa_dev,
>                                           u8 port_num)
> {
>          struct ib_sa_port *port;
>          unsigned long flags;
>          bool ret = false;
> 
>          port = &sa_dev->port[port_num - sa_dev->start_port];
>          spin_lock_irqsave(&port->classport_lock, flags);
>          if (!port->classport_info.valid)
>                  goto ret;
> 
>          if (port->classport_info.data.type == RDMA_CLASS_PORT_INFO_OPA)
>                  ret = opa_get_cpi_capmask2(&port->classport_info.data.opa)
> &
>                          OPA_CLASS_PORT_INFO_PR_SUPPORT;
> ret:
>          spin_unlock_irqrestore(&port->classport_lock, flags);
>          return ret;
> }
> 

Thanks for pointing this out. We'll look into it.

-Denny