Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] infiniband hfi1: fix misuse of %x in ipoib_tx.c
To:     "Marciniszyn, Mike" <mike.marciniszyn@cornelisnetworks.com>,
        Guo Zhi <qtxuning1999@sjtu.edu.cn>,
        "Dalessandro, Dennis" <dennis.dalessandro@cornelisnetworks.com>,
        "dledford@redhat.com" <dledford@redhat.com>
Cc:     "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <20210922134857.619602-1-qtxuning1999@sjtu.edu.cn>
 <CH0PR01MB71536ECA05AA44C4FAD83502F2A29@CH0PR01MB7153.prod.exchangelabs.com>
From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <276b9343-c23d-ac15-bb73-d7b42e7e7f0f@acm.org>
Date:   Wed, 22 Sep 2021 11:05:42 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.13.0
MIME-Version: 1.0
In-Reply-To: <CH0PR01MB71536ECA05AA44C4FAD83502F2A29@CH0PR01MB7153.prod.exchangelabs.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 9/22/21 10:51 AM, Marciniszyn, Mike wrote:
>> Subject: [PATCH] infiniband hfi1: fix misuse of %x in ipoib_tx.c
>>
>> Pointers should be printed with %p or %px rather than cast to (unsigned long
>> long) and printed with %llx.
>> Change %llx to %p to print the pointer.
>>
>> Signed-off-by: Guo Zhi <qtxuning1999@sjtu.edu.cn>
> 
> The unsigned long long was originally used to insure the entire accurate pointer as emitted.
> 
> This is to ensure the pointers in prints and event traces match values in stacks and register dumps.
> 
> I think the %p will obfuscate the pointer so %px is correct for our use case.

How about applying Guo's patch and adding a configuration option to the
kernel for disabling pointer hashing for %p and related format specifiers?
Pointer hashing is useful on production systems but not on development
systems.

Thanks,

Bart.