syzbot

netdevsim netdevsim3 eth1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim3 eth0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
==================================================================
BUG: KCSAN: data-race in __flush_work / wq_worker_running

read-write to 0xffff888237c2a860 of 4 bytes by task 28321 on cpu 0:
 wq_worker_running+0x96/0xe0 kernel/workqueue.c:880
 schedule_timeout+0xc1/0x290 kernel/time/timer.c:1935
 schedule_timeout_uninterruptible kernel/time/timer.c:1969 [inline]
 msleep+0x57/0x70 kernel/time/timer.c:2091
 nsim_fib6_rt_add drivers/net/netdevsim/fib.c:693 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:759 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x2776/0x2c30 drivers/net/netdevsim/fib.c:1492
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

read to 0xffff888237c2a860 of 4 bytes by task 30644 on cpu 1:
 __need_more_worker kernel/workqueue.c:785 [inline]
 insert_work kernel/workqueue.c:1365 [inline]
 insert_wq_barrier kernel/workqueue.c:2716 [inline]
 start_flush_work kernel/workqueue.c:3034 [inline]
 __flush_work+0x416/0x520 kernel/workqueue.c:3074
 flush_work+0x13/0x20 kernel/workqueue.c:3096
 nsim_fib_destroy+0x91/0x130 drivers/net/netdevsim/fib.c:1658
 nsim_dev_reload_destroy+0x20d/0x2e0 drivers/net/netdevsim/dev.c:1649
 nsim_dev_reload_down+0x73/0x90 drivers/net/netdevsim/dev.c:959
 devlink_reload+0x13e/0x480 net/core/devlink.c:4481
 devlink_nl_cmd_reload+0x52b/0x890 net/core/devlink.c:4602
 genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x7b1/0x850 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x13e/0x240 net/netlink/af_netlink.c:2501
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x58a/0x660 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x666/0x760 net/netlink/af_netlink.c:1921
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 ____sys_sendmsg+0x38f/0x500 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmsg+0x19a/0x230 net/socket.c:2565
 __do_sys_sendmsg net/socket.c:2574 [inline]
 __se_sys_sendmsg net/socket.c:2572 [inline]
 __x64_sys_sendmsg+0x42/0x50 net/socket.c:2572
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000001 -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 30644 Comm: syz-executor.3 Not tainted 6.0.0-rc3-syzkaller-00031-gc5e4d5e99162-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
==================================================================
netdevsim netdevsim3 eth0: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim3 eth1: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim3 eth2: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim3 eth3: set [1, 0] type 2 family 0 port 6081 - 0