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BUG: KCSAN: data-race in __mod_timer / expire_timers

write to 0xffff88813bd1b908 of 8 bytes by interrupt on cpu 1:
 expire_timers+0x11e/0x260 kernel/time/timer.c:1477
 __run_timers+0x358/0x3f0 kernel/time/timer.c:1745
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1758
 __do_softirq+0x13c/0x2c3 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu+0xb4/0xc0 kernel/softirq.c:422
 sysvec_apic_timer_interrupt+0x6e/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
 should_watch kernel/kcsan/core.c:264 [inline]
 check_access kernel/kcsan/core.c:627 [inline]
 __tsan_read1+0x14c/0x180 kernel/kcsan/core.c:837
 memcmp lib/string.c:939 [inline]
 strstr+0x9a/0xe0 lib/string.c:1006
 tomoyo_add_entry security/tomoyo/common.c:2022 [inline]
 tomoyo_supervisor+0x750/0xb40 security/tomoyo/common.c:2103
 tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline]
 tomoyo_path_number_perm+0x227/0x2d0 security/tomoyo/file.c:734
 tomoyo_file_ioctl+0x1c/0x20 security/tomoyo/tomoyo.c:329
 security_file_ioctl+0x45/0x90 security/security.c:1495
 __do_sys_ioctl fs/ioctl.c:747 [inline]
 __se_sys_ioctl+0x48/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813bd1b908 of 8 bytes by task 8399 on cpu 0:
 __mod_timer+0x44e/0xc10 kernel/time/timer.c:1035
 add_timer+0x38/0x50 kernel/time/timer.c:1142
 __queue_delayed_work+0xec/0x150 kernel/workqueue.c:1655
 mod_delayed_work_on+0x6a/0xd0 kernel/workqueue.c:1718
 mod_delayed_work include/linux/workqueue.h:537 [inline]
 addrconf_verify_rtnl+0x957/0x9b0 net/ipv6/addrconf.c:4566
 inet6_addr_add+0x892/0x9e0 net/ipv6/addrconf.c:2968
 inet6_rtm_newaddr+0x54d/0x1330 net/ipv6/addrconf.c:4869
 rtnetlink_rcv_msg+0x728/0x7c0 net/core/rtnetlink.c:5553
 netlink_rcv_skb+0x13e/0x240 net/netlink/af_netlink.c:2502
 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5571
 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
 netlink_unicast+0x5fc/0x6c0 net/netlink/af_netlink.c:1338
 netlink_sendmsg+0x6f8/0x7c0 net/netlink/af_netlink.c:1927
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 __sys_sendto+0x2a8/0x370 net/socket.c:1977
 __do_sys_sendto net/socket.c:1989 [inline]
 __se_sys_sendto net/socket.c:1985 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:1985
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8399 Comm: syz-executor.2 Not tainted 5.12.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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