Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Subject: Re: [PATCH] scsi: ibmvscsis: Silence -Warray-bounds warning
To:     Kees Cook <keescook@chromium.org>,
        Michael Cyr <mikecyr@linux.ibm.com>
Cc:     Stephen Rothwell <sfr@canb.auug.org.au>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
References: <20220208061231.3429486-1-keescook@chromium.org>
From:   Tyrel Datwyler <tyreld@linux.ibm.com>
Message-ID: <53b3e9c5-23c1-3825-8286-b4a65b69067b@linux.ibm.com>
Date:   Wed, 9 Feb 2022 15:53:21 -0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.13.0
In-Reply-To: <20220208061231.3429486-1-keescook@chromium.org>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
Precedence: bulk

On 2/7/22 10:12 PM, Kees Cook wrote:
> Instead of doing a cast to storage that is too small, add a union for
> the high 64 bits. Silences the warnings under -Warray-bounds:
> 
> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c: In function 'ibmvscsis_send_messages':
> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1934:44: error: array subscript 'struct viosrp_crq[0]' is partly outside array bounds of 'u64[1]' {aka 'long long unsigned int[1]'} [-Werror=array-bounds]
>  1934 |                                         crq->valid = VALID_CMD_RESP_EL;
>       |                                            ^~
> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1875:13: note: while referencing 'msg_hi'
>  1875 |         u64 msg_hi = 0;
>       |             ^~~~~~
> 
> There is no change to the resulting binary instructions.
> 
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Link: https://lore.kernel.org/lkml/20220125142430.75c3160e@canb.auug.org.au
> Cc: Michael Cyr <mikecyr@linux.ibm.com>
> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: Tyrel Datwyler <tyreld@linux.ibm.com>
> Cc: linux-scsi@vger.kernel.org
> Cc: target-devel@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c |  9 +++------

Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>