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BUG: KCSAN: data-race in __mod_timer / expire_timers

write to 0xffff88813bc1b908 of 8 bytes by interrupt on cpu 0:
 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
 run_ksoftirqd+0x13/0x20 kernel/softirq.c:652
 smpboot_thread_fn+0x34f/0x520 kernel/smpboot.c:165
 kthread+0x20b/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff88813bc1b908 of 8 bytes by task 8355 on cpu 1:
 __mod_timer+0x44e/0xc10 kernel/time/timer.c:1035
 mod_timer+0x1b/0x20 kernel/time/timer.c:1106
 sk_reset_timer+0x1f/0xa0 net/core/sock.c:2960
 tcp_send_delayed_ack+0x23e/0x250 net/ipv4/tcp_output.c:3932
 __tcp_ack_snd_check+0x2f9/0x510 net/ipv4/tcp_input.c:5419
 tcp_rcv_established+0x11f0/0x1330 net/ipv4/tcp_input.c:5848
 tcp_v4_do_rcv+0x278/0x4a0 net/ipv4/tcp_ipv4.c:1679
 sk_backlog_rcv include/net/sock.h:1016 [inline]
 __release_sock+0xf5/0x270 net/core/sock.c:2556
 release_sock+0x40/0x110 net/core/sock.c:3080
 tcp_recvmsg+0x153/0x430 net/ipv4/tcp.c:2551
 inet_recvmsg+0xa3/0x210 net/ipv4/af_inet.c:852
 sock_recvmsg_nosec net/socket.c:888 [inline]
 sock_recvmsg net/socket.c:906 [inline]
 sock_read_iter+0x19e/0x1e0 net/socket.c:979
 call_read_iter include/linux/fs.h:1971 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x565/0x5d0 fs/read_write.c:496
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 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: 1 PID: 8355 Comm: syz-fuzzer Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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