syzbot

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

write to 0xffffffff893a7488 of 304 bytes by interrupt on cpu 1:
 timekeeping_update_from_shadow+0x40d/0x440 kernel/time/timekeeping.c:829
 __timekeeping_advance+0xa5d/0xc10 kernel/time/timekeeping.c:2532
 timekeeping_advance kernel/time/timekeeping.c:2540 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2550
 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+0x8d/0x3d0 kernel/time/tick-sched.c:312
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x276/0x4f0 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x261/0x850 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 should_watch kernel/kcsan/core.c:277 [inline]
 check_access kernel/kcsan/core.c:752 [inline]
 __tsan_read4+0x107/0x190 kernel/kcsan/core.c:1024
 __unix_dgram_recvmsg+0x798/0x870 net/unix/af_unix.c:2672
 unix_dgram_recvmsg+0x7e/0x90 net/unix/af_unix.c:2686
 sock_recvmsg_nosec+0xc2/0xf0 net/socket.c:1137
 ____sys_recvmsg+0x26f/0x280 net/socket.c:2916
 ___sys_recvmsg+0x11f/0x3b0 net/socket.c:2960
 do_recvmmsg+0x1ef/0x560 net/socket.c:3055
 __sys_recvmmsg net/socket.c:3129 [inline]
 __do_sys_recvmmsg net/socket.c:3152 [inline]
 __se_sys_recvmmsg net/socket.c:3145 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3145
 x64_sys_call+0x80f/0x3020 arch/x86/include/generated/asm/syscalls_64.h:300
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff893a7498 of 8 bytes by task 2942 on cpu 0:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:426 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:449 [inline]
 ktime_get+0xcf/0x240 kernel/time/timekeeping.c:967
 ktime_get_ns include/linux/timekeeping.h:175 [inline]
 blk_time_get_ns block/blk.h:702 [inline]
 blk_account_io_start+0x2ef/0x3d0 block/blk-mq.c:1131
 blk_mq_bio_to_request block/blk-mq.c:2707 [inline]
 blk_mq_submit_bio+0xcd9/0x1130 block/blk-mq.c:3228
 __submit_bio+0x103/0x4f0 block/blk-core.c:635
 __submit_bio_noacct_mq block/blk-core.c:722 [inline]
 submit_bio_noacct_nocheck+0x153/0x620 block/blk-core.c:753
 submit_bio_noacct+0x746/0x980 block/blk-core.c:884
 submit_bio+0x2a4/0x2c0 block/blk-core.c:926
 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
 submit_bh_wbc+0x2e0/0x320 fs/buffer.c:2737
 submit_bh+0x1e/0x30 fs/buffer.c:2742
 jbd2_journal_commit_transaction+0x1546/0x3270 fs/jbd2/commit.c:755
 kjournald2+0x22e/0x3e0 fs/jbd2/journal.c:201
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x000001814d84c544 -> 0x000001814ed476b1

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2942 Comm: jbd2/sda1-8 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================