On 12/5/23 06:18, Stefan Hajnoczi wrote:
> Commit 4e0400525691 ("virtio-blk: support polling I/O") triggers the
> following gcc 13 W=1 warnings:
>
> drivers/block/virtio_blk.c: In function ‘init_vq’:
> drivers/block/virtio_blk.c:1077:68: warning: ‘%d’ directive output may be
> truncated writing between 1 and 11 bytes into a region of size 7
> [-Wformat-truncation=]
> 1077 | snprintf(vblk->vqs[i].name, VQ_NAME_LEN,
> "req_poll.%d", i);
> | ^~
> drivers/block/virtio_blk.c:1077:58: note: directive argument in the range
> [-2147483648, 65534]
> 1077 | snprintf(vblk->vqs[i].name, VQ_NAME_LEN,
> "req_poll.%d", i);
> |
> ^~~~~~~~~~~~~
> drivers/block/virtio_blk.c:1077:17: note: ‘snprintf’ output between 11 and 21
> bytes into a destination of size 16
> 1077 | snprintf(vblk->vqs[i].name, VQ_NAME_LEN,
> "req_poll.%d", i);
> |
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> This is a false positive because the lower bound -2147483648 is
> incorrect. The true range of i is [0, num_vqs - 1] where 0 < num_vqs <
> 65536.
>
> The code mixes int, unsigned short, and unsigned int types in addition
> to using "%d" for an unsigned value. The only place where a 16-bit value
> is needed is during the config space access. Use unsigned int and "%u"
> consistently to solve the compiler warning and clean up the code.
>
> Cc: Suwan Kim <suwan.kim...@gmail.com>
> Reported-by: kernel test robot <l...@intel.com>
> Closes:
> https://lore.kernel.org/oe-kbuild-all/202312041509.diyvet9h-...@intel.com/
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> ---
> drivers/block/virtio_blk.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> v2:
> - Use unsigned int instead of unsigned short [David]
>
>
Looks good.
Reviewed-by: Chaitanya Kulkarni <k...@nvidia.com>
-ck
