syzbot

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BUG: KCSAN: data-race in rt6_disable_ip / xfrm_lookup_with_ifid

write to 0xffff8881127b5600 of 8 bytes by task 58 on cpu 1:
 rt6_uncached_list_flush_dev net/ipv6/route.c:185 [inline]
 rt6_disable_ip+0x2f9/0x5e0 net/ipv6/route.c:4916
 addrconf_ifdown+0xa2/0xf20 net/ipv6/addrconf.c:3855
 addrconf_notify+0x2ff/0x950
 notifier_call_chain kernel/notifier.c:93 [inline]
 raw_notifier_call_chain+0x6f/0x1d0 kernel/notifier.c:461
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:1992
 call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
 call_netdevice_notifiers net/core/dev.c:2044 [inline]
 dev_close_many+0x174/0x240 net/core/dev.c:1585
 unregister_netdevice_many_notify+0x25d/0xf00 net/core/dev.c:11194
 unregister_netdevice_many+0x19/0x20 net/core/dev.c:11277
 cleanup_net+0x417/0x830 net/core/net_namespace.c:635
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
 worker_thread+0x526/0x730 kernel/workqueue.c:3393
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff8881127b5600 of 8 bytes by task 9 on cpu 0:
 xfrm_lookup_with_ifid+0x6b3/0x12e0 net/xfrm/xfrm_policy.c:3269
 xfrm_lookup+0x37/0x50 net/xfrm/xfrm_policy.c:3298
 icmp6_dst_alloc+0x2da/0x320 net/ipv6/route.c:3297
 mld_sendpack+0x2f6/0x6d0 net/ipv6/mcast.c:1807
 mld_send_cr net/ipv6/mcast.c:2119 [inline]
 mld_ifc_work+0x517/0x7e0 net/ipv6/mcast.c:2650
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
 worker_thread+0x526/0x730 kernel/workqueue.c:3393
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0xffff8881115e6000 -> 0xffff8881011ce000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.10.0-rc5-syzkaller-00018-g55027e689933 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: mld mld_ifc_work
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