syzbot

netlink: 24 bytes leftover after parsing attributes in process `syz.2.613'.
==================================================================
BUG: KCSAN: data-race in ktime_get_coarse_real_ts64_mg / 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
 its_return_thunk+0x0/0x10
 kernfs_root fs/kernfs/kernfs-internal.h:75 [inline]
 kernfs_link_sibling+0x237/0x320 fs/kernfs/dir.c:411
 kernfs_add_one+0x13c/0x280 fs/kernfs/dir.c:845
 __kernfs_create_file+0x145/0x180 fs/kernfs/file.c:1086
 sysfs_add_file_mode_ns+0x132/0x1b0 fs/sysfs/file.c:313
 create_files fs/sysfs/group.c:82 [inline]
 internal_create_group+0x441/0x9e0 fs/sysfs/group.c:189
 internal_create_groups fs/sysfs/group.c:229 [inline]
 sysfs_create_groups+0x3f/0xf0 fs/sysfs/group.c:255
 device_add_groups drivers/base/core.c:2837 [inline]
 device_add_attrs+0x64/0x3f0 drivers/base/core.c:2901
 device_add+0x37a/0x790 drivers/base/core.c:3645
 netdev_register_kobject+0x109/0x230 net/core/net-sysfs.c:2343
 register_netdevice+0xaaf/0x1160 net/core/dev.c:11420
 __ip_tunnel_create+0x31d/0x430 net/ipv4/ip_tunnel.c:268
 ip_tunnel_init_net+0x210/0x490 net/ipv4/ip_tunnel.c:1147
 ipip_init_net+0x35/0x40 net/ipv4/ipip.c:629
 ops_init+0x22a/0x2e0 net/core/net_namespace.c:137
 setup_net+0x9f/0x230 net/core/net_namespace.c:446
 copy_net_ns+0x310/0x450 net/core/net_namespace.c:579
 create_new_namespaces+0x20e/0x440 kernel/nsproxy.c:132
 copy_namespaces+0x1ad/0x210 kernel/nsproxy.c:195
 copy_process+0x10b1/0x2370 kernel/fork.c:2267
 kernel_clone+0x1a5/0x5e0 kernel/fork.c:2721
 __do_sys_clone kernel/fork.c:2862 [inline]
 __se_sys_clone kernel/fork.c:2846 [inline]
 __x64_sys_clone+0x143/0x180 kernel/fork.c:2846
 x64_sys_call+0x1222/0x3020 arch/x86/include/generated/asm/syscalls_64.h:57
 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 0xffffffff893a74f8 of 4 bytes by task 8762 on cpu 0:
 tk_xtime_coarse kernel/time/timekeeping.c:212 [inline]
 ktime_get_coarse_real_ts64_mg+0x89/0x1a0 kernel/time/timekeeping.c:2606
 current_time+0x41/0x240 fs/inode.c:2370
 need_cmtime_update fs/inode.c:2392 [inline]
 file_update_time_flags+0x83/0x2e0 fs/inode.c:2413
 file_update_time+0x17/0x20 fs/inode.c:2443
 fault_dirty_shared_page+0xc4/0x2d0 mm/memory.c:3710
 do_shared_fault mm/memory.c:5985 [inline]
 do_fault mm/memory.c:6031 [inline]
 do_pte_missing mm/memory.c:4550 [inline]
 handle_pte_fault mm/memory.c:6411 [inline]
 __handle_mm_fault mm/memory.c:6549 [inline]
 handle_mm_fault+0x1c66/0x2e70 mm/memory.c:6718
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x1290/0x1f10 mm/gup.c:1428
 __get_user_pages_locked mm/gup.c:1692 [inline]
 __gup_longterm_locked+0x2fa/0xe30 mm/gup.c:2481
 pin_user_pages+0x88/0xc0 mm/gup.c:3383
 xdp_umem_pin_pages+0xc0/0x200 net/xdp/xdp_umem.c:106
 xdp_umem_reg net/xdp/xdp_umem.c:232 [inline]
 xdp_umem_create+0x4eb/0x590 net/xdp/xdp_umem.c:265
 xsk_setsockopt+0x5ea/0x640 net/xdp/xsk.c:1654
 do_sock_setsockopt net/socket.c:2381 [inline]
 __sys_setsockopt+0x184/0x200 net/socket.c:2406
 __do_sys_setsockopt net/socket.c:2412 [inline]
 __se_sys_setsockopt net/socket.c:2409 [inline]
 __x64_sys_setsockopt+0x64/0x80 net/socket.c:2409
 x64_sys_call+0x2327/0x3020 arch/x86/include/generated/asm/syscalls_64.h:55
 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

value changed: 0x1aef978c -> 0x1b8832c6

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 8762 Comm: syz.2.613 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================