================================================================== BUG: KCSAN: data-race in __dev_queue_xmit / pfifo_fast_dequeue write to 0xffff8880b2728508 of 1 bytes by task 20379 on cpu 1: pfifo_fast_dequeue+0x49a/0x6e0 net/sched/sch_generic.c:660 dequeue_skb net/sched/sch_generic.c:263 [inline] qdisc_restart net/sched/sch_generic.c:366 [inline] __qdisc_run+0x14f/0xd40 net/sched/sch_generic.c:384 __dev_xmit_skb net/core/dev.c:3482 [inline] __dev_queue_xmit+0x1af5/0x1b60 net/core/dev.c:3842 dev_queue_xmit+0x21/0x30 net/core/dev.c:3906 neigh_hh_output include/net/neighbour.h:500 [inline] neigh_output include/net/neighbour.h:509 [inline] ip_finish_output2+0x83a/0xe40 net/ipv4/ip_output.c:228 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290 ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip_mc_output+0x143/0x620 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:436 [inline] ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125 ip_send_skb+0x35/0xb0 net/ipv4/ip_output.c:1555 udp_send_skb.isra.0+0x3ce/0x8c0 net/ipv4/udp.c:891 udp_sendmsg+0x1568/0x1900 net/ipv4/udp.c:1178 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0x9f/0xc0 net/socket.c:657 read to 0xffff8880b2728508 of 1 bytes by task 20383 on cpu 0: __dev_xmit_skb net/core/dev.c:3470 [inline] __dev_queue_xmit+0x9db/0x1b60 net/core/dev.c:3842 dev_queue_xmit+0x21/0x30 net/core/dev.c:3906 neigh_hh_output include/net/neighbour.h:500 [inline] neigh_output include/net/neighbour.h:509 [inline] ip_finish_output2+0x83a/0xe40 net/ipv4/ip_output.c:228 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290 ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip_mc_output+0x143/0x620 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:436 [inline] ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125 ip_send_skb+0x35/0xb0 net/ipv4/ip_output.c:1555 udp_send_skb.isra.0+0x3ce/0x8c0 net/ipv4/udp.c:891 udp_sendmsg+0x1568/0x1900 net/ipv4/udp.c:1178 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0x9f/0xc0 net/socket.c:657 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 20383 Comm: syz-executor.3 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================