==================================================================
BUG: KCSAN: data-race in mod_timer / timer_clear_idle

write to 0xffff88812bf1b6e4 of 1 bytes by task 0 on cpu 1:
 timer_clear_idle+0x42/0x50 kernel/time/timer.c:1675
 tick_nohz_restart_sched_tick kernel/time/tick-sched.c:839 [inline]
 __tick_nohz_idle_restart_tick+0x36/0x1b0 kernel/time/tick-sched.c:1140
 tick_nohz_idle_exit+0x1af/0x1e0 kernel/time/tick-sched.c:1181
 do_idle+0xb1/0x280 kernel/sched/idle.c:276
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355
 start_secondary+0x208/0x260 arch/x86/kernel/smpboot.c:264
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241

read to 0xffff88812bf1b6e4 of 1 bytes by task 7382 on cpu 0:
 forward_timer_base kernel/time/timer.c:892 [inline]
 __mod_timer kernel/time/timer.c:983 [inline]
 mod_timer+0x50d/0x7a0 kernel/time/timer.c:1100
 sk_reset_timer+0x2d/0x70 net/core/sock.c:2838
 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:234 [inline]
 tcp_reset_xmit_timer include/net/tcp.h:1279 [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:2447
 __tcp_push_pending_frames+0x7b/0x1d0 net/ipv4/tcp_output.c:2616
 tcp_push+0x1e9/0x3d0 net/ipv4/tcp.c:724
 tcp_sendmsg_locked+0x1d1e/0x1f30 net/ipv4/tcp.c:1403
 tcp_sendmsg+0x39/0x60 net/ipv4/tcp.c:1434
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7382 Comm: syz-fuzzer Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================