==================================================================
BUG: KCSAN: data-race in __run_timers / internal_add_timer

write to 0xffff888237c376d8 of 8 bytes by interrupt on cpu 1:
 enqueue_timer kernel/time/timer.c:597 [inline]
 internal_add_timer+0x13d/0x260 kernel/time/timer.c:609
 add_timer_on+0x262/0x2a0 kernel/time/timer.c:1180
 clocksource_watchdog+0xa74/0xac0 kernel/time/clocksource.c:478
 call_timer_fn+0x2e/0x1d0 kernel/time/timer.c:1417
 expire_timers+0x135/0x250 kernel/time/timer.c:1462
 __run_timers+0x358/0x420 kernel/time/timer.c:1731
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1744
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x9a/0xb0 kernel/softirq.c:636
 sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
 check_kcov_mode kernel/kcov.c:165 [inline]
 __sanitizer_cov_trace_pc+0x33/0x60 kernel/kcov.c:197
 __do_sys_wait4 kernel/exit.c:1707 [inline]
 __se_sys_wait4 kernel/exit.c:1701 [inline]
 __x64_sys_wait4+0xc9/0x100 kernel/exit.c:1701
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c376d8 of 8 bytes by interrupt on cpu 0:
 __run_timers+0x50/0x420 kernel/time/timer.c:1712
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1744
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x9a/0xb0 kernel/softirq.c:636
 sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
 write_comp_data kernel/kcov.c:240 [inline]
 __sanitizer_cov_trace_const_cmp4+0x90/0xa0 kernel/kcov.c:284
 wait_task_continued kernel/exit.c:1234 [inline]
 wait_consider_task+0x13a5/0x19e0 kernel/exit.c:1380
 do_wait_thread kernel/exit.c:1397 [inline]
 do_wait+0x182/0x640 kernel/exit.c:1514
 kernel_wait4+0x13c/0x1a0 kernel/exit.c:1677
 __do_sys_wait4 kernel/exit.c:1705 [inline]
 __se_sys_wait4 kernel/exit.c:1701 [inline]
 __x64_sys_wait4+0x7a/0x100 kernel/exit.c:1701
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000100021000 -> 0x0000000100020f8c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6097 Comm: syz-executor.2 Not tainted 5.14.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================