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virtio_blk: fix snprintf truncation compiler warning

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[ 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>
This commit is contained in:
Stefan Hajnoczi 2023-12-04 09:07:43 -05:00 committed by Greg Kroah-Hartman
parent ffcaafdb8b
commit 79aa992c80
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/block/virtio_blk.c
View File

@ -1021,12 +1021,12 @@ 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, };
@ -1070,13 +1070,13 @@ 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;
}