syzbot

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BUG: KCSAN: data-race in fib_release_info / free_fib_info

write to 0xffffffff86e253a0 of 4 bytes by task 15738 on cpu 1:
 free_fib_info net/ipv4/fib_semantics.c:252 [inline]
 fib_info_put include/net/ip_fib.h:575 [inline]
 fib_release_info+0x3e2/0x470 net/ipv4/fib_semantics.c:275
 fib_table_delete+0x915/0x940 net/ipv4/fib_trie.c:1762
 fib_magic+0x1b5/0x1e0 net/ipv4/fib_frontend.c:1089
 fib_del_ifaddr+0x90f/0xac0 net/ipv4/fib_frontend.c:1297
 fib_inetaddr_event+0x73/0x210 net/ipv4/fib_frontend.c:1428
 notifier_call_chain kernel/notifier.c:83 [inline]
 blocking_notifier_call_chain+0x73/0xf0 kernel/notifier.c:318
 __inet_del_ifa+0x507/0x870 net/ipv4/devinet.c:430
 inet_rtm_deladdr+0x3e7/0x450 net/ipv4/devinet.c:687
 rtnetlink_rcv_msg+0x745/0x7e0 net/core/rtnetlink.c:5571
 netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2491
 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5589
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x5fc/0x6c0 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x6e1/0x7d0 net/netlink/af_netlink.c:1916
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 ____sys_sendmsg+0x39a/0x510 net/socket.c:2409
 ___sys_sendmsg net/socket.c:2463 [inline]
 __sys_sendmsg+0x195/0x230 net/socket.c:2492
 __do_sys_sendmsg net/socket.c:2501 [inline]
 __se_sys_sendmsg net/socket.c:2499 [inline]
 __x64_sys_sendmsg+0x42/0x50 net/socket.c:2499
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffffff86e253a0 of 4 bytes by task 13089 on cpu 0:
 free_fib_info+0x35/0x80 net/ipv4/fib_semantics.c:252
 fib_info_put include/net/ip_fib.h:575 [inline]
 nsim_fib4_rt_destroy drivers/net/netdevsim/fib.c:294 [inline]
 nsim_fib4_rt_replace drivers/net/netdevsim/fib.c:403 [inline]
 nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:431 [inline]
 nsim_fib4_event drivers/net/netdevsim/fib.c:461 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:881 [inline]
 nsim_fib_event_work+0x15ca/0x2cf0 drivers/net/netdevsim/fib.c:1477
 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
 process_scheduled_works kernel/workqueue.c:2361 [inline]
 worker_thread+0x7df/0xa70 kernel/workqueue.c:2447
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

value changed: 0x00000504 -> 0x00000503

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13089 Comm: kworker/0:4 Tainted: G        W         5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_fib_event_work
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