==================================================================
BUG: KCSAN: data-race in expire_timers / try_to_del_timer_sync

write to 0xffff888237d376c8 of 8 bytes by interrupt on cpu 1:
 expire_timers+0x13d/0x250 kernel/time/timer.c:1465
 __run_timers+0x358/0x420 kernel/time/timer.c:1732
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1745
 __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_cmp8+0x8c/0x90 kernel/kcov.c:291
 daxdev_mapping_supported include/linux/dax.h:118 [inline]
 ext4_file_mmap+0x9d/0x120 fs/ext4/file.c:777
 call_mmap include/linux/fs.h:2119 [inline]
 mmap_region+0xbcb/0x1400 mm/mmap.c:1808
 do_mmap+0x73f/0xc40 mm/mmap.c:1584
 vm_mmap_pgoff+0xf9/0x1d0 mm/util.c:519
 vm_mmap+0x8c/0xb0 mm/util.c:538
 elf_map+0x139/0x240 fs/binfmt_elf.c:392
 load_elf_binary+0xfeb/0x2790 fs/binfmt_elf.c:1141
 search_binary_handler fs/exec.c:1721 [inline]
 exec_binprm+0x1ca/0x6e0 fs/exec.c:1762
 bprm_execve+0x3b6/0x530 fs/exec.c:1831
 kernel_execve+0x61b/0x640 fs/exec.c:1974
 call_usermodehelper_exec_async+0x1d8/0x290 kernel/umh.c:112
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

read to 0xffff888237d376c8 of 8 bytes by task 11 on cpu 0:
 try_to_del_timer_sync+0xe3/0x290 kernel/time/timer.c:1233
 del_timer_sync kernel/time/timer.c:1380 [inline]
 schedule_timeout+0x108/0x240 kernel/time/timer.c:1880
 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline]
 rcu_gp_kthread+0xbf7/0xec0 kernel/rcu/tree.c:2169
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

value changed: 0xffffc90000277e60 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11 Comm: rcu_sched Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================