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BUG: KCSAN: data-race in mod_timer / timer_clear_idle

read to 0xffff88812bf1b6e4 of 1 bytes by task 7220 on cpu 0:
 forward_timer_base kernel/time/timer.c:888 [inline]
 __mod_timer kernel/time/timer.c:979 [inline]
 mod_timer+0x50d/0x7a0 kernel/time/timer.c:1096
 sk_reset_timer+0x2d/0x70 net/core/sock.c:2830
 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:234 [inline]
 tcp_reset_xmit_timer include/net/tcp.h:1269 [inline]
 tcp_rearm_rto.part.0+0x190/0x240 net/ipv4/tcp_input.c:3009
 tcp_rearm_rto+0x4f/0x60 net/ipv4/tcp_input.c:3012
 tcp_event_new_data_sent+0x1bb/0x1c0 net/ipv4/tcp_output.c:77
 tcp_write_xmit+0xa16/0x3080 net/ipv4/tcp_output.c:2436
 __tcp_push_pending_frames+0x7b/0x1d0 net/ipv4/tcp_output.c:2605
 tcp_push+0x1e9/0x3d0 net/ipv4/tcp.c:724
 tcp_sendmsg_locked+0x1d1b/0x1ef0 net/ipv4/tcp.c:1402
 tcp_sendmsg+0x39/0x60 net/ipv4/tcp.c:1433
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 sock_write_iter+0x16b/0x210 net/socket.c:989
 call_write_iter include/linux/fs.h:1870 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483

write to 0xffff88812bf1b6e4 of 1 bytes by task 0 on cpu 1:
 timer_clear_idle+0x42/0x50 kernel/time/timer.c:1590
 tick_nohz_next_event+0x164/0x380 kernel/time/tick-sched.c:706
 __tick_nohz_idle_stop_tick kernel/time/tick-sched.c:940 [inline]
 tick_nohz_idle_stop_tick+0x3c2/0x670 kernel/time/tick-sched.c:970
 cpuidle_idle_call kernel/sched/idle.c:151 [inline]
 do_idle+0x1e0/0x2c0 kernel/sched/idle.c:263
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:354
 start_secondary+0x207/0x260 arch/x86/kernel/smpboot.c:264
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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