Re: Re: [PATCH net-next] virtio-net: fix possible unsigned integer overflow

Heng Qi
2023-02-01T06:48:19Z

On Wed, Feb 01, 2023 at 01:12:40PM +0800, kernel test robot wrote:
> Hi Michael,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on net-next/master]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Michael-S-Tsirkin/Re-PATCH-net-next-virtio-net-fix-possible-unsigned-integer-overflow/20230131-155257
> patch link: https://lore.kernel.org/r/20230131024630-mutt-send-email-mst%40kernel.org
> patch subject: Re: [PATCH net-next] virtio-net: fix possible unsigned integer overflow
> config: x86_64-defconfig (https://download.01.org/0day-ci/archive/20230201/202302011339.GBk75YVm-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
> reproduce (this is a W=1 build):
> # https://github.com/intel-lab-lkp/linux/commit/077b51b239749c6168bbda5ebe0bb3362d33e2bc
> git remote add linux-review https://github.com/intel-lab-lkp/linux
> git fetch --no-tags linux-review Michael-S-Tsirkin/Re-PATCH-net-next-virtio-net-fix-possible-unsigned-integer-overflow/20230131-155257
> git checkout 077b51b239749c6168bbda5ebe0bb3362d33e2bc
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> make W=1 O=build_dir ARCH=x86_64 olddefconfig
> make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
> drivers/net/virtio_net.c: In function 'receive_mergeable':
> >> drivers/net/virtio_net.c:1179:50: error: passing argument 8 of 'virtnet_build_xdp_buff_mrg' from incompatible pointer type [-Werror=incompatible-pointer-types]
> 1179 | &num_buf, &xdp_frags_truesz, stats);
> | ^~~~~~~~
> | |
> | int *
> drivers/net/virtio_net.c:999:44: note: expected 'u16 *' {aka 'short unsigned int *'} but argument is of type 'int *'
> 999 | u16 *num_buf,
> | ~~~~~^~~~~~~
> cc1: some warnings being treated as errors
>

This is a bug caused by the robot mistriggering and misidentifying the patch,
i.e. Michael's reply as a patch.

The original patch is at https://lore.kernel.org/all/20230131085004.98687-1-hengqi@linux.alibaba.com/ .

Thanks.

>
> vim +/virtnet_build_xdp_buff_mrg +1179 drivers/net/virtio_net.c
>
> ef75cb51f13941 Heng Qi 2023-01-14 1075
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1076 static struct sk_buff *receive_mergeable(struct net_device *dev,
> fdd819b21576c3 Michael S. Tsirkin 2014-10-07 1077 struct virtnet_info *vi,
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1078 struct receive_queue *rq,
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1079 void *buf,
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1080 void *ctx,
> 186b3c998c50fc Jason Wang 2017-09-19 1081 unsigned int len,
> 7d9d60fd4ab696 Toshiaki Makita 2018-07-23 1082 unsigned int *xdp_xmit,
> d46eeeaf99bcfa Jason Wang 2018-07-31 1083 struct virtnet_rq_stats *stats)
> 9ab86bbcf8be75 Shirley Ma 2010-01-29 1084 {
> 012873d057a449 Michael S. Tsirkin 2014-10-24 1085 struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
> 077b51b239749c Michael S. Tsirkin 2023-01-31 1086 int num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1087 struct page *page = virt_to_head_page(buf);
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1088 int offset = buf - page_address(page);
> f600b690501550 John Fastabend 2016-12-15 1089 struct sk_buff *head_skb, *curr_skb;
> f600b690501550 John Fastabend 2016-12-15 1090 struct bpf_prog *xdp_prog;
> 9ce6146ec7b507 Jesper Dangaard Brouer 2020-05-14 1091 unsigned int truesize = mergeable_ctx_to_truesize(ctx);
> 4941d472bf95b4 Jason Wang 2017-07-19 1092 unsigned int headroom = mergeable_ctx_to_headroom(ctx);
> ef75cb51f13941 Heng Qi 2023-01-14 1093 unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
> ef75cb51f13941 Heng Qi 2023-01-14 1094 unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
> 22174f79a44baf Heng Qi 2023-01-14 1095 unsigned int frame_sz, xdp_room;
> 9ce6146ec7b507 Jesper Dangaard Brouer 2020-05-14 1096 int err;
> f600b690501550 John Fastabend 2016-12-15 1097
> 56434a01b12e99 John Fastabend 2016-12-15 1098 head_skb = NULL;
> d46eeeaf99bcfa Jason Wang 2018-07-31 1099 stats->bytes += len - vi->hdr_len;
> 56434a01b12e99 John Fastabend 2016-12-15 1100
> ef75cb51f13941 Heng Qi 2023-01-14 1101 if (unlikely(len > truesize - room)) {
> ad993a95c50841 Xie Yongji 2021-05-31 1102 pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
> ef75cb51f13941 Heng Qi 2023-01-14 1103 dev->name, len, (unsigned long)(truesize - room));
> ad993a95c50841 Xie Yongji 2021-05-31 1104 dev->stats.rx_length_errors++;
> ad993a95c50841 Xie Yongji 2021-05-31 1105 goto err_skb;
> ad993a95c50841 Xie Yongji 2021-05-31 1106 }
> 6213f07cb542c9 Li RongQing 2021-10-09 1107
> 6213f07cb542c9 Li RongQing 2021-10-09 1108 if (likely(!vi->xdp_enabled)) {
> 6213f07cb542c9 Li RongQing 2021-10-09 1109 xdp_prog = NULL;
> 6213f07cb542c9 Li RongQing 2021-10-09 1110 goto skip_xdp;
> 6213f07cb542c9 Li RongQing 2021-10-09 1111 }
> 6213f07cb542c9 Li RongQing 2021-10-09 1112
> f600b690501550 John Fastabend 2016-12-15 1113 rcu_read_lock();
> f600b690501550 John Fastabend 2016-12-15 1114 xdp_prog = rcu_dereference(rq->xdp_prog);
> f600b690501550 John Fastabend 2016-12-15 1115 if (xdp_prog) {
> 22174f79a44baf Heng Qi 2023-01-14 1116 unsigned int xdp_frags_truesz = 0;
> 22174f79a44baf Heng Qi 2023-01-14 1117 struct skb_shared_info *shinfo;
> 44fa2dbd475996 Jesper Dangaard Brouer 2018-04-17 1118 struct xdp_frame *xdpf;
> 72979a6c35907b John Fastabend 2016-12-15 1119 struct page *xdp_page;
> 0354e4d19cd5de John Fastabend 2017-02-02 1120 struct xdp_buff xdp;
> 0354e4d19cd5de John Fastabend 2017-02-02 1121 void *data;
> f600b690501550 John Fastabend 2016-12-15 1122 u32 act;
> 22174f79a44baf Heng Qi 2023-01-14 1123 int i;
> f600b690501550 John Fastabend 2016-12-15 1124
> 3d62b2a0db505b Jason Wang 2018-05-22 1125 /* Transient failure which in theory could occur if
> 3d62b2a0db505b Jason Wang 2018-05-22 1126 * in-flight packets from before XDP was enabled reach
> 3d62b2a0db505b Jason Wang 2018-05-22 1127 * the receive path after XDP is loaded.
> 3d62b2a0db505b Jason Wang 2018-05-22 1128 */
> 3d62b2a0db505b Jason Wang 2018-05-22 1129 if (unlikely(hdr->hdr.gso_type))
> 3d62b2a0db505b Jason Wang 2018-05-22 1130 goto err_xdp;
> 3d62b2a0db505b Jason Wang 2018-05-22 1131
> ef75cb51f13941 Heng Qi 2023-01-14 1132 /* Now XDP core assumes frag size is PAGE_SIZE, but buffers
> ef75cb51f13941 Heng Qi 2023-01-14 1133 * with headroom may add hole in truesize, which
> ef75cb51f13941 Heng Qi 2023-01-14 1134 * make their length exceed PAGE_SIZE. So we disabled the
> ef75cb51f13941 Heng Qi 2023-01-14 1135 * hole mechanism for xdp. See add_recvbuf_mergeable().
> 9ce6146ec7b507 Jesper Dangaard Brouer 2020-05-14 1136 */
> ef75cb51f13941 Heng Qi 2023-01-14 1137 frame_sz = truesize;
> 9ce6146ec7b507 Jesper Dangaard Brouer 2020-05-14 1138
> 22174f79a44baf Heng Qi 2023-01-14 1139 /* This happens when headroom is not enough because
> 22174f79a44baf Heng Qi 2023-01-14 1140 * of the buffer was prefilled before XDP is set.
> 22174f79a44baf Heng Qi 2023-01-14 1141 * This should only happen for the first several packets.
> 22174f79a44baf Heng Qi 2023-01-14 1142 * In fact, vq reset can be used here to help us clean up
> 22174f79a44baf Heng Qi 2023-01-14 1143 * the prefilled buffers, but many existing devices do not
> 22174f79a44baf Heng Qi 2023-01-14 1144 * support it, and we don't want to bother users who are
> 22174f79a44baf Heng Qi 2023-01-14 1145 * using xdp normally.
> 3cc81a9aac4382 Jason Wang 2018-03-02 1146 */
> 22174f79a44baf Heng Qi 2023-01-14 1147 if (!xdp_prog->aux->xdp_has_frags &&
> 22174f79a44baf Heng Qi 2023-01-14 1148 (num_buf > 1 || headroom < virtnet_get_headroom(vi))) {
> 72979a6c35907b John Fastabend 2016-12-15 1149 /* linearize data for XDP */
> 56a86f84b8332a Jason Wang 2016-12-23 1150 xdp_page = xdp_linearize_page(rq, &num_buf,
> 4941d472bf95b4 Jason Wang 2017-07-19 1151 page, offset,
> 4941d472bf95b4 Jason Wang 2017-07-19 1152 VIRTIO_XDP_HEADROOM,
> 4941d472bf95b4 Jason Wang 2017-07-19 1153 &len);
> 9ce6146ec7b507 Jesper Dangaard Brouer 2020-05-14 1154 frame_sz = PAGE_SIZE;
> 9ce6146ec7b507 Jesper Dangaard Brouer 2020-05-14 1155
> 72979a6c35907b John Fastabend 2016-12-15 1156 if (!xdp_page)
> f600b690501550 John Fastabend 2016-12-15 1157 goto err_xdp;
> 2de2f7f40ef923 John Fastabend 2017-02-02 1158 offset = VIRTIO_XDP_HEADROOM;
> 22174f79a44baf Heng Qi 2023-01-14 1159 } else if (unlikely(headroom < virtnet_get_headroom(vi))) {
> 22174f79a44baf Heng Qi 2023-01-14 1160 xdp_room = SKB_DATA_ALIGN(VIRTIO_XDP_HEADROOM +
> 22174f79a44baf Heng Qi 2023-01-14 1161 sizeof(struct skb_shared_info));
> 22174f79a44baf Heng Qi 2023-01-14 1162 if (len + xdp_room > PAGE_SIZE)
> 22174f79a44baf Heng Qi 2023-01-14 1163 goto err_xdp;
> 22174f79a44baf Heng Qi 2023-01-14 1164
> 22174f79a44baf Heng Qi 2023-01-14 1165 xdp_page = alloc_page(GFP_ATOMIC);
> 22174f79a44baf Heng Qi 2023-01-14 1166 if (!xdp_page)
> 22174f79a44baf Heng Qi 2023-01-14 1167 goto err_xdp;
> 22174f79a44baf Heng Qi 2023-01-14 1168
> 22174f79a44baf Heng Qi 2023-01-14 1169 memcpy(page_address(xdp_page) + VIRTIO_XDP_HEADROOM,
> 22174f79a44baf Heng Qi 2023-01-14 1170 page_address(page) + offset, len);
> 22174f79a44baf Heng Qi 2023-01-14 1171 frame_sz = PAGE_SIZE;
> 22174f79a44baf Heng Qi 2023-01-14 1172 offset = VIRTIO_XDP_HEADROOM;
> 72979a6c35907b John Fastabend 2016-12-15 1173 } else {
> 72979a6c35907b John Fastabend 2016-12-15 1174 xdp_page = page;
> f600b690501550 John Fastabend 2016-12-15 1175 }
> f600b690501550 John Fastabend 2016-12-15 1176
> 0354e4d19cd5de John Fastabend 2017-02-02 1177 data = page_address(xdp_page) + offset;
> 22174f79a44baf Heng Qi 2023-01-14 1178 err = virtnet_build_xdp_buff_mrg(dev, vi, rq, &xdp, data, len, frame_sz,
> 22174f79a44baf Heng Qi 2023-01-14 @1179 &num_buf, &xdp_frags_truesz, stats);
> 22174f79a44baf Heng Qi 2023-01-14 1180 if (unlikely(err))
> 22174f79a44baf Heng Qi 2023-01-14 1181 goto err_xdp_frags;
> 754b8a21a96d5f Jesper Dangaard Brouer 2018-01-03 1182
> 0354e4d19cd5de John Fastabend 2017-02-02 1183 act = bpf_prog_run_xdp(xdp_prog, &xdp);
> d46eeeaf99bcfa Jason Wang 2018-07-31 1184 stats->xdp_packets++;
> 0354e4d19cd5de John Fastabend 2017-02-02 1185
> 56434a01b12e99 John Fastabend 2016-12-15 1186 switch (act) {
> 56434a01b12e99 John Fastabend 2016-12-15 1187 case XDP_PASS:
> fab89bafa95b6f Heng Qi 2023-01-14 1188 if (unlikely(xdp_page != page))
> 1830f8935f3b17 Jason Wang 2016-12-23 1189 put_page(page);
> fab89bafa95b6f Heng Qi 2023-01-14 1190 head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
> fab89bafa95b6f Heng Qi 2023-01-14 1191 rcu_read_unlock();
> 1830f8935f3b17 Jason Wang 2016-12-23 1192 return head_skb;
> 56434a01b12e99 John Fastabend 2016-12-15 1193 case XDP_TX:
> d46eeeaf99bcfa Jason Wang 2018-07-31 1194 stats->xdp_tx++;
> 1b698fa5d8ef95 Lorenzo Bianconi 2020-05-28 1195 xdpf = xdp_convert_buff_to_frame(&xdp);
> 7a542bee27c6a5 Xuan Zhuo 2022-08-04 1196 if (unlikely(!xdpf)) {
> fab89bafa95b6f Heng Qi 2023-01-14 1197 netdev_dbg(dev, "convert buff to frame failed for xdp\n");
> fab89bafa95b6f Heng Qi 2023-01-14 1198 goto err_xdp_frags;
> 7a542bee27c6a5 Xuan Zhuo 2022-08-04 1199 }
> ca9e83b4a55bfa Jason Wang 2018-07-31 1200 err = virtnet_xdp_xmit(dev, 1, &xdpf, 0);
> fdc13979f91e66 Lorenzo Bianconi 2021-03-08 1201 if (unlikely(!err)) {
> fdc13979f91e66 Lorenzo Bianconi 2021-03-08 1202 xdp_return_frame_rx_napi(xdpf);
> fdc13979f91e66 Lorenzo Bianconi 2021-03-08 1203 } else if (unlikely(err < 0)) {
> 0354e4d19cd5de John Fastabend 2017-02-02 1204 trace_xdp_exception(vi->dev, xdp_prog, act);
> fab89bafa95b6f Heng Qi 2023-01-14 1205 goto err_xdp_frags;
> 11b7d897ccc1fb Jesper Dangaard Brouer 2018-02-20 1206 }
> 2471c75efed325 Jesper Dangaard Brouer 2018-06-26 1207 *xdp_xmit |= VIRTIO_XDP_TX;
> 72979a6c35907b John Fastabend 2016-12-15 1208 if (unlikely(xdp_page != page))
> 5d458a13dd59d0 Jason Wang 2018-05-22 1209 put_page(page);
> 56434a01b12e99 John Fastabend 2016-12-15 1210 rcu_read_unlock();
> 56434a01b12e99 John Fastabend 2016-12-15 1211 goto xdp_xmit;
> 3cc81a9aac4382 Jason Wang 2018-03-02 1212 case XDP_REDIRECT:
> d46eeeaf99bcfa Jason Wang 2018-07-31 1213 stats->xdp_redirects++;
> 3cc81a9aac4382 Jason Wang 2018-03-02 1214 err = xdp_do_redirect(dev, &xdp, xdp_prog);
> fab89bafa95b6f Heng Qi 2023-01-14 1215 if (err)
> fab89bafa95b6f Heng Qi 2023-01-14 1216 goto err_xdp_frags;
> 2471c75efed325 Jesper Dangaard Brouer 2018-06-26 1217 *xdp_xmit |= VIRTIO_XDP_REDIR;
> 3cc81a9aac4382 Jason Wang 2018-03-02 1218 if (unlikely(xdp_page != page))
> 6890418bbb780f Jason Wang 2018-05-22 1219 put_page(page);
> 3cc81a9aac4382 Jason Wang 2018-03-02 1220 rcu_read_unlock();
> 3cc81a9aac4382 Jason Wang 2018-03-02 1221 goto xdp_xmit;
> 56434a01b12e99 John Fastabend 2016-12-15 1222 default:
> c8064e5b4adac5 Paolo Abeni 2021-11-30 1223 bpf_warn_invalid_xdp_action(vi->dev, xdp_prog, act);
> df561f6688fef7 Gustavo A. R. Silva 2020-08-23 1224 fallthrough;
> 0354e4d19cd5de John Fastabend 2017-02-02 1225 case XDP_ABORTED:
> 0354e4d19cd5de John Fastabend 2017-02-02 1226 trace_xdp_exception(vi->dev, xdp_prog, act);
> df561f6688fef7 Gustavo A. R. Silva 2020-08-23 1227 fallthrough;
> 0354e4d19cd5de John Fastabend 2017-02-02 1228 case XDP_DROP:
> fab89bafa95b6f Heng Qi 2023-01-14 1229 goto err_xdp_frags;
> f600b690501550 John Fastabend 2016-12-15 1230 }
> 22174f79a44baf Heng Qi 2023-01-14 1231 err_xdp_frags:
> 22174f79a44baf Heng Qi 2023-01-14 1232 if (unlikely(xdp_page != page))
> 22174f79a44baf Heng Qi 2023-01-14 1233 __free_pages(xdp_page, 0);
> 22174f79a44baf Heng Qi 2023-01-14 1234
> 22174f79a44baf Heng Qi 2023-01-14 1235 if (xdp_buff_has_frags(&xdp)) {
> 22174f79a44baf Heng Qi 2023-01-14 1236 shinfo = xdp_get_shared_info_from_buff(&xdp);
> 22174f79a44baf Heng Qi 2023-01-14 1237 for (i = 0; i < shinfo->nr_frags; i++) {
> 22174f79a44baf Heng Qi 2023-01-14 1238 xdp_page = skb_frag_page(&shinfo->frags[i]);
> 22174f79a44baf Heng Qi 2023-01-14 1239 put_page(xdp_page);
> 22174f79a44baf Heng Qi 2023-01-14 1240 }
> 22174f79a44baf Heng Qi 2023-01-14 1241 }
> 22174f79a44baf Heng Qi 2023-01-14 1242
> 22174f79a44baf Heng Qi 2023-01-14 1243 goto err_xdp;
> 56434a01b12e99 John Fastabend 2016-12-15 1244 }
> f600b690501550 John Fastabend 2016-12-15 1245 rcu_read_unlock();
> ab7db91705e95e Michael Dalton 2014-01-16 1246
> 6213f07cb542c9 Li RongQing 2021-10-09 1247 skip_xdp:
> 18117a842ab029 Heng Qi 2023-01-14 1248 head_skb = page_to_skb(vi, rq, page, offset, len, truesize);
> f600b690501550 John Fastabend 2016-12-15 1249 curr_skb = head_skb;
> 3f2c31d90327f2 Mark McLoughlin 2008-11-16 1250
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1251 if (unlikely(!curr_skb))
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1252 goto err_skb;
> 9ab86bbcf8be75 Shirley Ma 2010-01-29 1253 while (--num_buf) {
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1254 int num_skb_frags;
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1255
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1256 buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx);
> 03e9f8a05bce73 Yunjian Wang 2017-12-04 1257 if (unlikely(!buf)) {
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1258 pr_debug("%s: rx error: %d buffers out of %d missing\n",
> fdd819b21576c3 Michael S. Tsirkin 2014-10-07 1259 dev->name, num_buf,
> 012873d057a449 Michael S. Tsirkin 2014-10-24 1260 virtio16_to_cpu(vi->vdev,
> 012873d057a449 Michael S. Tsirkin 2014-10-24 1261 hdr->num_buffers));
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1262 dev->stats.rx_length_errors++;
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1263 goto err_buf;
> 3f2c31d90327f2 Mark McLoughlin 2008-11-16 1264 }
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1265
> d46eeeaf99bcfa Jason Wang 2018-07-31 1266 stats->bytes += len;
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1267 page = virt_to_head_page(buf);
> 28b39bc7c57e79 Jason Wang 2017-07-19 1268
> 28b39bc7c57e79 Jason Wang 2017-07-19 1269 truesize = mergeable_ctx_to_truesize(ctx);
> ef75cb51f13941 Heng Qi 2023-01-14 1270 headroom = mergeable_ctx_to_headroom(ctx);
> ef75cb51f13941 Heng Qi 2023-01-14 1271 tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
> ef75cb51f13941 Heng Qi 2023-01-14 1272 room = SKB_DATA_ALIGN(headroom + tailroom);
> ef75cb51f13941 Heng Qi 2023-01-14 1273 if (unlikely(len > truesize - room)) {
> 56da5fd04e3d51 Dan Carpenter 2017-04-06 1274 pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
> ef75cb51f13941 Heng Qi 2023-01-14 1275 dev->name, len, (unsigned long)(truesize - room));
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1276 dev->stats.rx_length_errors++;
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1277 goto err_skb;
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1278 }
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1279
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1280 num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1281 if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
> 2613af0ed18a11 Michael Dalton 2013-10-28 1282 struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1283
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1284 if (unlikely(!nskb))
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1285 goto err_skb;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1286 if (curr_skb == head_skb)
> 2613af0ed18a11 Michael Dalton 2013-10-28 1287 skb_shinfo(curr_skb)->frag_list = nskb;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1288 else
> 2613af0ed18a11 Michael Dalton 2013-10-28 1289 curr_skb->next = nskb;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1290 curr_skb = nskb;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1291 head_skb->truesize += nskb->truesize;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1292 num_skb_frags = 0;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1293 }
> 2613af0ed18a11 Michael Dalton 2013-10-28 1294 if (curr_skb != head_skb) {
> 2613af0ed18a11 Michael Dalton 2013-10-28 1295 head_skb->data_len += len;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1296 head_skb->len += len;
> fb51879dbceab9 Michael Dalton 2014-01-16 1297 head_skb->truesize += truesize;
> 2613af0ed18a11 Michael Dalton 2013-10-28 1298 }
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1299 offset = buf - page_address(page);
> ba275241030cfe Jason Wang 2013-11-01 1300 if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
> ba275241030cfe Jason Wang 2013-11-01 1301 put_page(page);
> ba275241030cfe Jason Wang 2013-11-01 1302 skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
> fb51879dbceab9 Michael Dalton 2014-01-16 1303 len, truesize);
> ba275241030cfe Jason Wang 2013-11-01 1304 } else {
> 2613af0ed18a11 Michael Dalton 2013-10-28 1305 skb_add_rx_frag(curr_skb, num_skb_frags, page,
> fb51879dbceab9 Michael Dalton 2014-01-16 1306 offset, len, truesize);
> ba275241030cfe Jason Wang 2013-11-01 1307 }
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1308 }
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1309
> 5377d75823ff90 Johannes Berg 2015-08-19 1310 ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1311 return head_skb;
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1312
> f600b690501550 John Fastabend 2016-12-15 1313 err_xdp:
> f600b690501550 John Fastabend 2016-12-15 1314 rcu_read_unlock();
> d46eeeaf99bcfa Jason Wang 2018-07-31 1315 stats->xdp_drops++;
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1316 err_skb:
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1317 put_page(page);
> 850e088d5bbb33 Jason Wang 2018-05-22 1318 while (num_buf-- > 1) {
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1319 buf = virtqueue_get_buf(rq->vq, &len);
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1320 if (unlikely(!buf)) {
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1321 pr_debug("%s: rx error: %d buffers missing\n",
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1322 dev->name, num_buf);
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1323 dev->stats.rx_length_errors++;
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1324 break;
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1325 }
> d46eeeaf99bcfa Jason Wang 2018-07-31 1326 stats->bytes += len;
> 680557cf79f826 Michael S. Tsirkin 2017-03-06 1327 page = virt_to_head_page(buf);
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1328 put_page(page);
> 9ab86bbcf8be75 Shirley Ma 2010-01-29 1329 }
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1330 err_buf:
> d46eeeaf99bcfa Jason Wang 2018-07-31 1331 stats->drops++;
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1332 dev_kfree_skb(head_skb);
> 56434a01b12e99 John Fastabend 2016-12-15 1333 xdp_xmit:
> 8fc3b9e9a22977 Michael S. Tsirkin 2013-11-28 1334 return NULL;
> 3f2c31d90327f2 Mark McLoughlin 2008-11-16 1335 }
> 23cde76d801246 Mark McLoughlin 2008-06-08 1336
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests