==================================================================
BUG: KCSAN: data-race in ktime_get / timekeeping_update_from_shadow

write to 0xffffffff895f4508 of 320 bytes by interrupt on cpu 1:
 timekeeping_update_from_shadow+0x448/0x480 kernel/time/timekeeping.c:866
 __timekeeping_advance+0xb36/0xcf0 kernel/time/timekeeping.c:2663
 timekeeping_advance kernel/time/timekeeping.c:2671 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2681
 tick_do_update_jiffies64+0x169/0x1c0 kernel/time/tick-sched.c:149
 tick_sched_do_timer kernel/time/tick-sched.c:253 [inline]
 tick_nohz_handler+0x88/0x380 kernel/time/tick-sched.c:310
 __run_hrtimer kernel/time/hrtimer.c:2074 [inline]
 __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2131
 hrtimer_interrupt+0x27b/0x860 kernel/time/hrtimer.c:2250
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 blk_complete_reqs block/blk-mq.c:1222 [inline]
 blk_done_softirq+0x77/0xb0 block/blk-mq.c:1227
 handle_softirqs+0xcc/0x2a0 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0x44/0xe0 kernel/softirq.c:758
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x74/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 preempt_schedule_irq+0x27/0x50 kernel/sched/core.c:7599
 raw_irqentry_exit_cond_resched+0x49/0x60 kernel/entry/common.c:145
 irqentry_exit_to_kernel_mode_preempt+0x2b/0x40 include/linux/irq-entry-common.h:468
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x7d/0x610 kernel/entry/common.c:167
 sysvec_apic_timer_interrupt+0x44/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 syscall_enter_from_user_mode_work include/linux/entry-common.h:142 [inline]
 do_syscall_64+0x88/0x360 arch/x86/entry/syscall_64.c:81
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff895f4528 of 8 bytes by task 13549 on cpu 0:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:477 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:482 [inline]
 ktime_get+0x130/0x240 kernel/time/timekeeping.c:1004
 ktime_get_ns include/linux/timekeeping.h:174 [inline]
 blk_time_get_ns block/blk.h:734 [inline]
 blk_account_io_start+0x376/0x450 block/blk-mq.c:1100
 blk_mq_bio_to_request block/blk-mq.c:2676 [inline]
 blk_mq_submit_bio+0xba2/0x1120 block/blk-mq.c:3182
 __submit_bio+0x54/0x3d0 block/blk-core.c:673
 __submit_bio_noacct_mq block/blk-core.c:756 [inline]
 submit_bio_noacct_nocheck+0x153/0x620 block/blk-core.c:790
 submit_bio_noacct+0x760/0x980 block/blk-core.c:925
 submit_bio+0x2a4/0x2c0 block/blk-core.c:966
 bio_chain_and_submit+0x84/0xb0 block/bio.c:376
 __blkdev_issue_zero_pages+0x1f7/0x240 block/blk-lib.c:215
 blkdev_issue_zero_pages block/blk-lib.c:231 [inline]
 blkdev_issue_zeroout+0x3a1/0x4f0 block/blk-lib.c:312
 blk_ioctl_zeroout block/ioctl.c:244 [inline]
 blkdev_common_ioctl+0x1a07/0x2060 block/ioctl.c:667
 blkdev_ioctl+0x31f/0x460 block/ioctl.c:792
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x239d/0x2550 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000976f1b6f9ae42 -> 0x000a0f8837291208

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 13549 Comm: syz.7.2621 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================