drivers/net/virtio_net.c:6456:36: warning: 'sprintf' may write a terminating nul past the end of the destination
From: kernel test robot
Date: Thu Jul 02 2026 - 00:46:04 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 4a50a141f05a8d1737661b19ee22ff8455b94409
commit: e7d4c1c5a54648fd5b787a4a0f81521ec7260bcd virtio: introduce extended features
date: 12 months ago
config: arm64-randconfig-002-20260702 (https://download.01.org/0day-ci/archive/20260702/202607021239.0UXE4ICC-lkp@xxxxxxxxx/config)
compiler: aarch64-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260702/202607021239.0UXE4ICC-lkp@xxxxxxxxx/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
| Fixes: e7d4c1c5a546 ("virtio: introduce extended features")
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202607021239.0UXE4ICC-lkp@xxxxxxxxx/
All warnings (new ones prefixed by >>):
drivers/net/virtio_net.c: In function 'virtnet_probe':
>> drivers/net/virtio_net.c:6456:36: warning: 'sprintf' may write a terminating nul past the end of the destination [-Wformat-overflow=]
sprintf(vi->rq[i].name, "input.%u", i);
^
drivers/net/virtio_net.c:6456:3: note: 'sprintf' output between 8 and 17 bytes into a destination of size 16
sprintf(vi->rq[i].name, "input.%u", i);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/virtio_net.c:6457:35: warning: '%u' directive writing between 1 and 10 bytes into a region of size 9 [-Wformat-overflow=]
sprintf(vi->sq[i].name, "output.%u", i);
^~
drivers/net/virtio_net.c:6457:27: note: directive argument in the range [0, 2147483647]
sprintf(vi->sq[i].name, "output.%u", i);
^~~~~~~~~~~
drivers/net/virtio_net.c:6457:3: note: 'sprintf' output between 9 and 18 bytes into a destination of size 16
sprintf(vi->sq[i].name, "output.%u", i);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +/sprintf +6456 drivers/net/virtio_net.c
d85b758f72b05a Michael S. Tsirkin 2017-03-09 6415
986a4f4d452dec Jason Wang 2012-12-07 6416 static int virtnet_find_vqs(struct virtnet_info *vi)
3f9c10b0d478a3 Amit Shah 2011-12-22 6417 {
c2c6325e1645b5 Jiri Pirko 2024-07-08 6418 struct virtqueue_info *vqs_info;
986a4f4d452dec Jason Wang 2012-12-07 6419 struct virtqueue **vqs;
e3fe8d28c67bf6 Zhu Yanjun 2024-01-04 6420 int ret = -ENOMEM;
e3fe8d28c67bf6 Zhu Yanjun 2024-01-04 6421 int total_vqs;
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6422 bool *ctx;
e3fe8d28c67bf6 Zhu Yanjun 2024-01-04 6423 u16 i;
986a4f4d452dec Jason Wang 2012-12-07 6424
986a4f4d452dec Jason Wang 2012-12-07 6425 /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
986a4f4d452dec Jason Wang 2012-12-07 6426 * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
986a4f4d452dec Jason Wang 2012-12-07 6427 * possible control vq.
986a4f4d452dec Jason Wang 2012-12-07 6428 */
986a4f4d452dec Jason Wang 2012-12-07 6429 total_vqs = vi->max_queue_pairs * 2 +
986a4f4d452dec Jason Wang 2012-12-07 6430 virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
986a4f4d452dec Jason Wang 2012-12-07 6431
986a4f4d452dec Jason Wang 2012-12-07 6432 /* Allocate space for find_vqs parameters */
6396bb221514d2 Kees Cook 2018-06-12 6433 vqs = kcalloc(total_vqs, sizeof(*vqs), GFP_KERNEL);
986a4f4d452dec Jason Wang 2012-12-07 6434 if (!vqs)
986a4f4d452dec Jason Wang 2012-12-07 6435 goto err_vq;
c2c6325e1645b5 Jiri Pirko 2024-07-08 6436 vqs_info = kcalloc(total_vqs, sizeof(*vqs_info), GFP_KERNEL);
c2c6325e1645b5 Jiri Pirko 2024-07-08 6437 if (!vqs_info)
c2c6325e1645b5 Jiri Pirko 2024-07-08 6438 goto err_vqs_info;
192f68cf35f5ee Jason Wang 2017-07-19 6439 if (!vi->big_packets || vi->mergeable_rx_bufs) {
6396bb221514d2 Kees Cook 2018-06-12 6440 ctx = kcalloc(total_vqs, sizeof(*ctx), GFP_KERNEL);
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6441 if (!ctx)
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6442 goto err_ctx;
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6443 } else {
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6444 ctx = NULL;
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6445 }
986a4f4d452dec Jason Wang 2012-12-07 6446
986a4f4d452dec Jason Wang 2012-12-07 6447 /* Parameters for control virtqueue, if any */
986a4f4d452dec Jason Wang 2012-12-07 6448 if (vi->has_cvq) {
c2c6325e1645b5 Jiri Pirko 2024-07-08 6449 vqs_info[total_vqs - 1].name = "control";
986a4f4d452dec Jason Wang 2012-12-07 6450 }
986a4f4d452dec Jason Wang 2012-12-07 6451
986a4f4d452dec Jason Wang 2012-12-07 6452 /* Allocate/initialize parameters for send/receive virtqueues */
986a4f4d452dec Jason Wang 2012-12-07 6453 for (i = 0; i < vi->max_queue_pairs; i++) {
c2c6325e1645b5 Jiri Pirko 2024-07-08 6454 vqs_info[rxq2vq(i)].callback = skb_recv_done;
c2c6325e1645b5 Jiri Pirko 2024-07-08 6455 vqs_info[txq2vq(i)].callback = skb_xmit_done;
e3fe8d28c67bf6 Zhu Yanjun 2024-01-04 @6456 sprintf(vi->rq[i].name, "input.%u", i);
e3fe8d28c67bf6 Zhu Yanjun 2024-01-04 6457 sprintf(vi->sq[i].name, "output.%u", i);
c2c6325e1645b5 Jiri Pirko 2024-07-08 6458 vqs_info[rxq2vq(i)].name = vi->rq[i].name;
c2c6325e1645b5 Jiri Pirko 2024-07-08 6459 vqs_info[txq2vq(i)].name = vi->sq[i].name;
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6460 if (ctx)
c2c6325e1645b5 Jiri Pirko 2024-07-08 6461 vqs_info[rxq2vq(i)].ctx = true;
986a4f4d452dec Jason Wang 2012-12-07 6462 }
986a4f4d452dec Jason Wang 2012-12-07 6463
6c85d6b653caeb Jiri Pirko 2024-07-08 6464 ret = virtio_find_vqs(vi->vdev, total_vqs, vqs, vqs_info, NULL);
986a4f4d452dec Jason Wang 2012-12-07 6465 if (ret)
986a4f4d452dec Jason Wang 2012-12-07 6466 goto err_find;
3f9c10b0d478a3 Amit Shah 2011-12-22 6467
986a4f4d452dec Jason Wang 2012-12-07 6468 if (vi->has_cvq) {
986a4f4d452dec Jason Wang 2012-12-07 6469 vi->cvq = vqs[total_vqs - 1];
986a4f4d452dec Jason Wang 2012-12-07 6470 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
f646968f8f7c62 Patrick McHardy 2013-04-19 6471 vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
986a4f4d452dec Jason Wang 2012-12-07 6472 }
3f9c10b0d478a3 Amit Shah 2011-12-22 6473
986a4f4d452dec Jason Wang 2012-12-07 6474 for (i = 0; i < vi->max_queue_pairs; i++) {
986a4f4d452dec Jason Wang 2012-12-07 6475 vi->rq[i].vq = vqs[rxq2vq(i)];
d85b758f72b05a Michael S. Tsirkin 2017-03-09 6476 vi->rq[i].min_buf_len = mergeable_min_buf_len(vi, vi->rq[i].vq);
986a4f4d452dec Jason Wang 2012-12-07 6477 vi->sq[i].vq = vqs[txq2vq(i)];
986a4f4d452dec Jason Wang 2012-12-07 6478 }
3f9c10b0d478a3 Amit Shah 2011-12-22 6479
2fa3c8a8b23041 Tonghao Zhang 2018-05-31 6480 /* run here: ret == 0. */
3f9c10b0d478a3 Amit Shah 2011-12-22 6481
3f9c10b0d478a3 Amit Shah 2011-12-22 6482
986a4f4d452dec Jason Wang 2012-12-07 6483 err_find:
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6484 kfree(ctx);
d45b897b11eaf9 Michael S. Tsirkin 2017-03-06 6485 err_ctx:
c2c6325e1645b5 Jiri Pirko 2024-07-08 6486 kfree(vqs_info);
c2c6325e1645b5 Jiri Pirko 2024-07-08 6487 err_vqs_info:
986a4f4d452dec Jason Wang 2012-12-07 6488 kfree(vqs);
986a4f4d452dec Jason Wang 2012-12-07 6489 err_vq:
986a4f4d452dec Jason Wang 2012-12-07 6490 return ret;
3f9c10b0d478a3 Amit Shah 2011-12-22 6491 }
986a4f4d452dec Jason Wang 2012-12-07 6492
:::::: The code at line 6456 was first introduced by commit
:::::: e3fe8d28c67bf6c291e920c6d04fa22afa14e6e4 virtio_net: Fix "‘%d’ directive writing between 1 and 11 bytes into a region of size 10" warnings
:::::: TO: Zhu Yanjun <yanjun.zhu@xxxxxxxxx>
:::::: CC: Jakub Kicinski <kuba@xxxxxxxxxx>
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