syzbot

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BUG: KCSAN: data-race in fib_table_lookup / fib_table_lookup

write to 0xffff888114e0fb7a of 1 bytes by task 18421 on cpu 0:
 fib_alias_accessed net/ipv4/fib_lookup.h:32 [inline]
 fib_table_lookup+0x370/0xd60 net/ipv4/fib_trie.c:1584
 __ip_dev_find+0x119/0x230 net/ipv4/devinet.c:168
 ip_route_output_key_hash_rcu+0x30d/0x12e0 net/ipv4/route.c:2722
 ip_route_output_key_hash net/ipv4/route.c:2683 [inline]
 __ip_route_output_key include/net/route.h:169 [inline]
 ip_route_output_flow+0x76/0x120 net/ipv4/route.c:2911
 udp_sendmsg+0xeda/0x1390 net/ipv4/udp.c:1450
 inet_sendmsg+0xaf/0xd0 net/ipv4/af_inet.c:851
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x102/0x180 net/socket.c:733
 ____sys_sendmsg+0x326/0x4b0 net/socket.c:2573
 ___sys_sendmsg net/socket.c:2627 [inline]
 __sys_sendmmsg+0x227/0x4b0 net/socket.c:2716
 __do_sys_sendmmsg net/socket.c:2743 [inline]
 __se_sys_sendmmsg net/socket.c:2740 [inline]
 __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2740
 x64_sys_call+0x29aa/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888114e0fb7a of 1 bytes by task 18428 on cpu 1:
 fib_alias_accessed net/ipv4/fib_lookup.h:31 [inline]
 fib_table_lookup+0x347/0xd60 net/ipv4/fib_trie.c:1584
 __inet_dev_addr_type net/ipv4/fib_frontend.c:225 [inline]
 inet_addr_type_dev_table+0x141/0x260 net/ipv4/fib_frontend.c:267
 fib_del_ifaddr+0x902/0xa60 net/ipv4/fib_frontend.c:1328
 fib_inetaddr_event+0x77/0x200 net/ipv4/fib_frontend.c:1456
 notifier_call_chain kernel/notifier.c:85 [inline]
 blocking_notifier_call_chain+0x94/0x200 kernel/notifier.c:380
 __inet_del_ifa+0x4cf/0x7e0 net/ipv4/devinet.c:459
 inet_del_ifa net/ipv4/devinet.c:496 [inline]
 inetdev_destroy net/ipv4/devinet.c:336 [inline]
 inetdev_event+0x64f/0xc60 net/ipv4/devinet.c:1664
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0x6f/0x1d0 kernel/notifier.c:453
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:2206
 call_netdevice_notifiers_extack net/core/dev.c:2244 [inline]
 call_netdevice_notifiers net/core/dev.c:2258 [inline]
 unregister_netdevice_many_notify+0x98a/0x1280 net/core/dev.c:11884
 rtnl_delete_link net/core/rtnetlink.c:3486 [inline]
 rtnl_dellink+0x38b/0x590 net/core/rtnetlink.c:3528
 rtnetlink_rcv_msg+0x651/0x710 net/core/rtnetlink.c:6912
 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2533
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6939
 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
 netlink_unicast+0x599/0x670 net/netlink/af_netlink.c:1338
 netlink_sendmsg+0x5cc/0x6e0 net/netlink/af_netlink.c:1882
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:733
 ____sys_sendmsg+0x326/0x4b0 net/socket.c:2573
 ___sys_sendmsg net/socket.c:2627 [inline]
 __sys_sendmsg+0x19d/0x230 net/socket.c:2659
 __do_sys_sendmsg net/socket.c:2664 [inline]
 __se_sys_sendmsg net/socket.c:2662 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2662
 x64_sys_call+0x2734/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 18428 Comm: syz.7.5290 Not tainted 6.14.0-rc6-syzkaller-00003-g4d872d51bc9d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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