EXT4-fs (loop3): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
==================================================================
BUG: KCSAN: data-race in ktime_get / timekeeping_update_from_shadow

write to 0xffffffff893c34c8 of 304 bytes by interrupt on cpu 0:
 timekeeping_update_from_shadow+0x40d/0x440 kernel/time/timekeeping.c:835
 __timekeeping_advance+0xa68/0xc10 kernel/time/timekeeping.c:2613
 timekeeping_advance kernel/time/timekeeping.c:2621 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2631
 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:2032 [inline]
 __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2096
 hrtimer_interrupt+0x257/0x810 kernel/time/hrtimer.c:2215
 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+0x6f/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 __sanitizer_cov_trace_pc+0x5c/0x70 kernel/kcov.c:233
 __alloc_skb+0x2ec/0x6f0 net/core/skbuff.c:705
 alloc_skb include/linux/skbuff.h:1386 [inline]
 netlink_alloc_large_skb+0xbf/0xf0 net/netlink/af_netlink.c:1185
 netlink_sendmsg+0x40c/0x6f0 net/netlink/af_netlink.c:1875
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x411/0x470 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0x76/0x90 net/socket.c:2255
 x64_sys_call+0x2d35/0x3020 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff893c34e8 of 8 bytes by task 13653 on cpu 1:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:450 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:455 [inline]
 ktime_get+0x130/0x240 kernel/time/timekeeping.c:973
 ktime_get_ns include/linux/timekeeping.h:175 [inline]
 blk_time_get_ns block/blk.h:730 [inline]
 blk_account_io_start+0x371/0x450 block/blk-mq.c:1100
 blk_mq_bio_to_request block/blk-mq.c:2676 [inline]
 blk_mq_submit_bio+0xbb2/0x1150 block/blk-mq.c:3182
 __submit_bio+0x103/0x4e0 block/blk-core.c:678
 __submit_bio_noacct_mq block/blk-core.c:763 [inline]
 submit_bio_noacct_nocheck+0x153/0x620 block/blk-core.c:797
 submit_bio_noacct+0x700/0x920 block/blk-core.c:928
 submit_bio+0x2a4/0x2c0 block/blk-core.c:969
 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline]
 __bh_submit+0x2db/0x310 fs/buffer.c:1225
 bh_submit fs/buffer.c:1239 [inline]
 __sync_dirty_buffer+0x15d/0x220 fs/buffer.c:2801
 sync_dirty_buffer+0x1a/0x30 fs/buffer.c:2814
 ext4_write_inode+0x29c/0x3c0 fs/ext4/inode.c:5799
 write_inode fs/fs-writeback.c:1607 [inline]
 __writeback_single_inode+0x327/0x660 fs/fs-writeback.c:1850
 writeback_single_inode+0x16d/0x400 fs/fs-writeback.c:1906
 sync_inode_metadata+0x6e/0xa0 fs/fs-writeback.c:3080
 mmb_fsync_noflush+0xfa/0x140 fs/buffer.c:663
 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline]
 ext4_sync_file+0x1f2/0x6d0 fs/ext4/fsync.c:160
 vfs_fsync_range+0xc5/0xe0 fs/sync.c:186
 generic_write_sync include/linux/fs.h:2666 [inline]
 ext4_buffered_write_iter+0x426/0x480 fs/ext4/file.c:322
 ext4_file_write_iter+0x38e/0xef0 fs/ext4/file.c:-1
 iter_file_splice_write+0x6a0/0xa60 fs/splice.c:736
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x156/0x280 fs/splice.c:1159
 splice_direct_to_actor+0x2f9/0x680 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x37d/0x640 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64 fs/read_write.c:1418 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1418
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0038b3dc6abe1faf -> 0x00394c72ea9e4a4a

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13653 Comm: syz.3.2336 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
==================================================================