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 <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Signed-off-by: Stefan Hajnoczi <[email protected]>
---
drivers/block/virtio_blk.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
v2:
- Use unsigned int instead of unsigned short [David]
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index d53d6aa8ee69..dc69a40fbf08 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -1019,20 +1019,23 @@ static void virtblk_config_changed(struct virtio_device *vdev)
static int init_vq(struct virtio_blk *vblk)
{
int err;
- int i;
+ unsigned int i;
vq_callback_t **callbacks;
const char **names;
struct virtqueue **vqs;
- unsigned short num_vqs;
+ unsigned int num_vqs;
unsigned int num_poll_vqs;
struct virtio_device *vdev = vblk->vdev;
struct irq_affinity desc = { 0, };
+ u16 num_vqs_u16;
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
struct virtio_blk_config, num_queues,
- &num_vqs);
+ &num_vqs_u16);
if (err)
num_vqs = 1;
+ else
+ num_vqs = num_vqs_u16;
if (!err && !num_vqs) {
dev_err(&vdev->dev, "MQ advertised but zero queues reported\n");
@@ -1068,13 +1071,13 @@ static int init_vq(struct virtio_blk *vblk)
for (i = 0; i < num_vqs - num_poll_vqs; i++) {
callbacks[i] = virtblk_done;
- snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
+ snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%u", i);
names[i] = vblk->vqs[i].name;
}
for (; i < num_vqs; i++) {
callbacks[i] = NULL;
- snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i);
+ snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%u", i);
names[i] = vblk->vqs[i].name;
}
--
2.43.0
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 <[email protected]>
> Reported-by: kernel test robot <[email protected]>
> Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
> Signed-off-by: Stefan Hajnoczi <[email protected]>
> ---
> 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 <[email protected]>
-ck