linux-kernel - Re: [axboe-block:nvme-passthru-wip 10/19] drivers/nvme/host/ioctl.c:47:19: error: cast to pointer from integer of different size

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Date:   Fri, 8 Oct 2021 06:35:02 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        kernel test robot <lkp@...el.com>
Cc:     Kanchan Joshi <joshi.k@...sung.com>, kbuild-all@...ts.01.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Anuj Gupta <anuj20.g@...sung.com>
Subject: Re: [axboe-block:nvme-passthru-wip 10/19]
 drivers/nvme/host/ioctl.c:47:19: error: cast to pointer from integer of
 different size

On 10/8/21 2:19 AM, Geert Uytterhoeven wrote:
> On Fri, Oct 8, 2021 at 12:12 AM kernel test robot <lkp@...el.com> wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git nvme-passthru-wip
>> head:   9c18980ac90053bcdb21594eae48935d89bf389c
>> commit: 5cc445dd8df6e06f3482711aa590170450364393 [10/19] nvme: wire-up support for async-passthru on char-device.
>> config: m68k-allmodconfig (attached as .config)
>> compiler: m68k-linux-gcc (GCC) 11.2.0
>> reproduce (this is a W=1 build):
>>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>         chmod +x ~/bin/make.cross
>>         # https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/commit/?id=5cc445dd8df6e06f3482711aa590170450364393
>>         git remote add axboe-block https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
>>         git fetch --no-tags axboe-block nvme-passthru-wip
>>         git checkout 5cc445dd8df6e06f3482711aa590170450364393
>>         # save the attached .config to linux build tree
>>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=m68k
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@...el.com>
>>
>> All errors (new ones prefixed by >>):
>>
>>    drivers/nvme/host/ioctl.c: In function 'nvme_pt_task_cb':
>>>> drivers/nvme/host/ioctl.c:47:19: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>       47 |         ptcmd64 = (void __user *) bcmd->unused2[0];
>>          |                   ^
>>    drivers/nvme/host/ioctl.c:62:58: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>       62 |                 struct nvme_passthru_cmd __user *ptcmd = (void *)bcmd->unused2[0];
>>          |                                                          ^
>>    drivers/nvme/host/ioctl.c: In function 'nvme_ns_async_ioctl':
>>    drivers/nvme/host/ioctl.c:472:29: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>      472 |         void __user *argp = (void __user *) bcmd->unused2[0];
>>          |                             ^
>>    cc1: all warnings being treated as errors
>>
>>
>> vim +47 drivers/nvme/host/ioctl.c
>>
>>     39
>>     40  static void nvme_pt_task_cb(struct io_uring_cmd *ioucmd)
>>     41  {
>>     42          struct uring_cmd_data *ucd;
>>     43          struct nvme_passthru_cmd64 __user *ptcmd64 = NULL;
>>     44          struct block_uring_cmd *bcmd;
>>     45
>>     46          bcmd = (struct block_uring_cmd *) &ioucmd->pdu;
>>   > 47          ptcmd64 = (void __user *) bcmd->unused2[0];
> 
> Casts from u64 to a pointer on 32-bit need an intermediate cast to uintptr_t:
> 
>     ptcmd64 = (void __user *)(uintptr_t)bcmd->unused2[0];
> 
> Note that you can improve on the naming, as people may be surprised
> discovering "unused2" is actually used ;-)

There's a reason the branch is called -wip, it's just a hodge podge of
stuff. Not sure why the kernel test robot bothers reporting failures
publicly for that...

-- 
Jens Axboe