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

[Geert Uytterhoeven]

On Fri, Oct 8, 2021 at 12:12 AM kernel test robot <lkp@xxxxxxxxx> 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@xxxxxxxxx>
>
> 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 ;-)

>     48          ucd = (struct uring_cmd_data *) nvme_ioucmd_data_addr(ioucmd);
>     49
>     50          if (ucd->meta) {
>     51                  void __user *umeta = nvme_to_user_ptr(ptcmd64->metadata);
>     52
>     53                  if (!ucd->status)
>     54                          if (copy_to_user(umeta, ucd->meta, ptcmd64->metadata_len))
>     55                                  ucd->status = -EFAULT;
>     56                  kfree(ucd->meta);
>     57          }
>     58          if (likely(bcmd->ioctl_cmd == NVME_IOCTL_IO64_CMD)) {
>     59                  if (put_user(ucd->result, &ptcmd64->result))
>     60                          ucd->status = -EFAULT;
>     61          } else {
>     62                  struct nvme_passthru_cmd __user *ptcmd = (void *)bcmd->unused2[0];
>     63
>     64                  if (put_user(ucd->result, &ptcmd->result))
>     65                          ucd->status = -EFAULT;
>     66          }
>     67          io_uring_cmd_done(ioucmd, ucd->status);
>     68  }
>     69
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx



-- 
Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds