syzbot

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BUG: KCSAN: data-race in __netdev_update_features / netif_skb_features

write to 0xffff8881178040b8 of 8 bytes by task 14616 on cpu 1:
 __netdev_update_features+0xd42/0xf60 net/core/dev.c:10597
 netdev_update_features+0x28/0x90 net/core/dev.c:10613
 br_del_if+0x1bf/0x1e0 net/bridge/br_if.c:751
 br_del_slave+0x24/0x30 net/bridge/br_device.c:380
 do_set_master net/core/rtnetlink.c:2912 [inline]
 do_setlink+0x94e/0x2370 net/core/rtnetlink.c:3125
 rtnl_group_changelink net/core/rtnetlink.c:3747 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3894 [inline]
 rtnl_newlink+0xcf9/0x1250 net/core/rtnetlink.c:4022
 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

read to 0xffff8881178040b8 of 8 bytes by task 9 on cpu 0:
 netif_skb_features+0x39/0x730 net/core/dev.c:3761
 validate_xmit_skb+0x26/0x830 net/core/dev.c:3875
 __dev_queue_xmit+0xdfe/0x2090 net/core/dev.c:4641
 dev_queue_xmit include/linux/netdevice.h:3313 [inline]
 neigh_hh_output include/net/neighbour.h:523 [inline]
 neigh_output include/net/neighbour.h:537 [inline]
 ip6_finish_output2+0x9d9/0xd60 net/ipv6/ip6_output.c:141
 ip6_finish_output+0x438/0x540 net/ipv6/ip6_output.c:226
 NF_HOOK_COND include/linux/netfilter.h:303 [inline]
 ip6_output+0xf5/0x230 net/ipv6/ip6_output.c:247
 dst_output include/net/dst.h:459 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 mld_sendpack+0x421/0x6d0 net/ipv6/mcast.c:1868
 mld_send_cr net/ipv6/mcast.c:2169 [inline]
 mld_ifc_work+0x51a/0x7e0 net/ipv6/mcast.c:2702
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4db/0xa20 kernel/workqueue.c:3319
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3400
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00002007ffdd48e9 -> 0x00002007ffff48e9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.14.0-rc4-syzkaller-00169-g1e15510b71c9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: mld mld_ifc_work
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