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BUG: KCSAN: data-race in do_sys_poll / pollwake

write to 0xffffc90001147bc0 of 4 bytes by task 12 on cpu 1:
 __pollwake fs/select.c:195 [inline]
 pollwake+0xb6/0x100 fs/select.c:215
 __wake_up_common kernel/sched/wait.c:89 [inline]
 __wake_up_common_lock kernel/sched/wait.c:106 [inline]
 __wake_up_sync_key+0x52/0x80 kernel/sched/wait.c:173
 sock_def_readable+0x70/0x190 net/core/sock.c:3583
 __netlink_sendskb net/netlink/af_netlink.c:1259 [inline]
 netlink_broadcast_deliver net/netlink/af_netlink.c:1390 [inline]
 do_one_broadcast net/netlink/af_netlink.c:1477 [inline]
 netlink_broadcast_filtered+0x9c0/0xc00 net/netlink/af_netlink.c:1522
 nlmsg_multicast_filtered include/net/netlink.h:1151 [inline]
 nlmsg_multicast include/net/netlink.h:1170 [inline]
 nlmsg_notify+0xcf/0x170 net/netlink/af_netlink.c:2577
 rtnl_notify+0x76/0x90 net/core/rtnetlink.c:958
 inet6_rt_notify+0x116/0x190 net/ipv6/route.c:6349
 fib6_add_rt2node+0xc31/0x1720 net/ipv6/ip6_fib.c:1282
 fib6_add+0x5b9/0xe00 net/ipv6/ip6_fib.c:1535
 __ip6_ins_rt net/ipv6/route.c:1351 [inline]
 ip6_ins_rt+0x73/0xb0 net/ipv6/route.c:1361
 __ipv6_ifa_notify+0x332/0x880 net/ipv6/addrconf.c:6286
 ipv6_ifa_notify net/ipv6/addrconf.c:6325 [inline]
 addrconf_dad_completed+0xdb/0x890 net/ipv6/addrconf.c:4324
 addrconf_dad_work+0x8ac/0xbf0 net/ipv6/addrconf.c:-1
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x489/0x510 kernel/kthread.c:464
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffc90001147bc0 of 4 bytes by task 3033 on cpu 0:
 poll_schedule_timeout fs/select.c:240 [inline]
 do_poll fs/select.c:958 [inline]
 do_sys_poll+0x99c/0xbd0 fs/select.c:1009
 __do_sys_ppoll fs/select.c:1115 [inline]
 __se_sys_ppoll+0x1b9/0x200 fs/select.c:1095
 __x64_sys_ppoll+0x67/0x80 fs/select.c:1095
 x64_sys_call+0x2de5/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:272
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 101 PID: 3033 Comm: dhcpcd Not tainted 6.16.0-rc4-syzkaller-00324-g1f988d0788f5 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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