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BUG: KCSAN: data-race in mod_timer / run_timer_softirq

read to 0xffff88812c01da88 of 8 bytes by task 8012 on cpu 1:
 __mod_timer kernel/time/timer.c:1026 [inline]
 mod_timer+0x1ec/0x7a0 kernel/time/timer.c:1100
 mld_ifc_start_timer+0x4d/0xf0 net/ipv6/mcast.c:1053
 mld_ifc_event net/ipv6/mcast.c:2492 [inline]
 mld_ifc_event+0x74/0x90 net/ipv6/mcast.c:2487
 igmp6_group_added+0x1c0/0x260 net/ipv6/mcast.c:692
 __ipv6_dev_mc_inc+0x4e0/0x760 net/ipv6/mcast.c:931
 ipv6_dev_mc_inc+0x29/0x40 net/ipv6/mcast.c:938
 addrconf_join_solict.part.0+0x7d/0xa0 net/ipv6/addrconf.c:2149
 addrconf_join_solict net/ipv6/addrconf.c:3939 [inline]
 addrconf_dad_begin net/ipv6/addrconf.c:3939 [inline]
 addrconf_dad_work+0x10b/0xba0 net/ipv6/addrconf.c:4066
 process_one_work+0x3d4/0x890 kernel/workqueue.c:2264
 worker_thread+0xa0/0x800 kernel/workqueue.c:2410
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

write to 0xffff88812c01da88 of 8 bytes by interrupt on cpu 0:
 expire_timers kernel/time/timer.c:1445 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x496/0xcd0 kernel/time/timer.c:1786
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xbb/0xe0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0xe6/0x280 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 security_sock_rcv_skb+0x32/0xa0 security/security.c:2049
 sk_filter_trim_cap+0x7c/0x510 net/core/filter.c:108
 sk_filter include/linux/filter.h:806 [inline]
 netlink_unicast+0x144/0x4d0 net/netlink/af_netlink.c:1330
 netlink_ack+0x38b/0x680 net/netlink/af_netlink.c:2447
 netlink_rcv_skb+0x22a/0x260 net/netlink/af_netlink.c:2483
 rtnetlink_rcv+0x26/0x30 net/core/rtnetlink.c:5442
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x3a6/0x4d0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x4d3/0x8b0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 __sys_sendto+0x21f/0x320 net/socket.c:1985
 __do_sys_sendto net/socket.c:1997 [inline]
 __se_sys_sendto net/socket.c:1993 [inline]
 __x64_sys_sendto+0x89/0xb0 net/socket.c:1993
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7997 Comm: syz-executor.2 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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