| Message ID | 20231205141840.1854409-1-stefanha@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] virtio_blk: fix snprintf truncation compiler warning | expand |
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.kim027@gmail.com> > Reported-by: kernel test robot <lkp@intel.com> > Closes: https://lore.kernel.org/oe-kbuild-all/202312041509.DIyvEt9h-lkp@intel.com/ > Signed-off-by: Stefan Hajnoczi <stefanha@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 <kch@nvidia.com> -ck
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; }
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.kim027@gmail.com> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202312041509.DIyvEt9h-lkp@intel.com/ Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- drivers/block/virtio_blk.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) v2: - Use unsigned int instead of unsigned short [David]