From: Stefan Hajnoczi stefanha@redhat.com
[ Upstream commit b8e0792449928943c15d1af9f63816911d139267 ]
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. Use unsigned short and "%u" consistently to solve the compiler warning.
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 Message-Id: 20231204140743.1487843-1-stefanha@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/virtio_blk.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index efa5535a8e1d8..3124837aa406f 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -609,12 +609,12 @@ static void virtblk_config_changed(struct virtio_device *vdev) static int init_vq(struct virtio_blk *vblk) { int err; - int i; + unsigned short i; vq_callback_t **callbacks; const char **names; struct virtqueue **vqs; unsigned short num_vqs; - unsigned int num_poll_vqs; + unsigned short num_poll_vqs; struct virtio_device *vdev = vblk->vdev; struct irq_affinity desc = { 0, };
@@ -658,13 +658,13 @@ 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; }