drivers/block/virtio_blk.c:570:68: warning: '%d' directive output may be truncated writing between 1 and 11 bytes into a region of size 7

[kernel test robot <lkp@intel.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   33cc938e65a98f1d29d0a18403dbbee050dcad9a
commit: 4e0400525691d0e676dbe002641f9a61261f1e1b virtio-blk: support polling I/O
date:   1 year, 6 months ago
config: x86_64-buildonly-randconfig-006-20230906 (https://download.01.org/0day-ci/archive/20231204/202312041509.DIyvEt9h-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231204/202312041509.DIyvEt9h-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312041509.DIyvEt9h-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/block/virtio_blk.c: In function 'init_vq':
>> drivers/block/virtio_blk.c:570:68: warning: '%d' directive output may be truncated writing between 1 and 11 bytes into a region of size 7 [-Wformat-truncation=]
     570 |                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i);
         |                                                                    ^~
   drivers/block/virtio_blk.c:570:58: note: directive argument in the range [-2147483648, 65534]
     570 |                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i);
         |                                                          ^~~~~~~~~~~~~
   drivers/block/virtio_blk.c:570:17: note: 'snprintf' output between 11 and 21 bytes into a destination of size 16
     570 |                 snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +570 drivers/block/virtio_blk.c

   511	
   512	static int init_vq(struct virtio_blk *vblk)
   513	{
   514		int err;
   515		int i;
   516		vq_callback_t **callbacks;
   517		const char **names;
   518		struct virtqueue **vqs;
   519		unsigned short num_vqs;
   520		unsigned int num_poll_vqs;
   521		struct virtio_device *vdev = vblk->vdev;
   522		struct irq_affinity desc = { 0, };
   523	
   524		err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
   525					   struct virtio_blk_config, num_queues,
   526					   &num_vqs);
   527		if (err)
   528			num_vqs = 1;
   529	
   530		if (!err && !num_vqs) {
   531			dev_err(&vdev->dev, "MQ advertised but zero queues reported\n");
   532			return -EINVAL;
   533		}
   534	
   535		num_vqs = min_t(unsigned int,
   536				min_not_zero(num_request_queues, nr_cpu_ids),
   537				num_vqs);
   538	
   539		num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);
   540	
   541		vblk->io_queues[HCTX_TYPE_DEFAULT] = num_vqs - num_poll_vqs;
   542		vblk->io_queues[HCTX_TYPE_READ] = 0;
   543		vblk->io_queues[HCTX_TYPE_POLL] = num_poll_vqs;
   544	
   545		dev_info(&vdev->dev, "%d/%d/%d default/read/poll queues\n",
   546					vblk->io_queues[HCTX_TYPE_DEFAULT],
   547					vblk->io_queues[HCTX_TYPE_READ],
   548					vblk->io_queues[HCTX_TYPE_POLL]);
   549	
   550		vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
   551		if (!vblk->vqs)
   552			return -ENOMEM;
   553	
   554		names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL);
   555		callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL);
   556		vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
   557		if (!names || !callbacks || !vqs) {
   558			err = -ENOMEM;
   559			goto out;
   560		}
   561	
   562		for (i = 0; i < num_vqs - num_poll_vqs; i++) {
   563			callbacks[i] = virtblk_done;
   564			snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
   565			names[i] = vblk->vqs[i].name;
   566		}
   567	
   568		for (; i < num_vqs; i++) {
   569			callbacks[i] = NULL;
 > 570			snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i);
   571			names[i] = vblk->vqs[i].name;
   572		}
   573	
   574		/* Discover virtqueues and write information to configuration.  */
   575		err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
   576		if (err)
   577			goto out;
   578	
   579		for (i = 0; i < num_vqs; i++) {
   580			spin_lock_init(&vblk->vqs[i].lock);
   581			vblk->vqs[i].vq = vqs[i];
   582		}
   583		vblk->num_vqs = num_vqs;
   584	
   585	out:
   586		kfree(vqs);
   587		kfree(callbacks);
   588		kfree(names);
   589		if (err)
   590			kfree(vblk->vqs);
   591		return err;
   592	}
   593	

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