INFO: task syz-executor:30861 blocked for more than 144 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:21960 pid:30861 tgid:30861 ppid:1 task_flags:0x40014c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 wb_wait_for_completion+0x15f/0x260 fs/fs-writeback.c:216 sync_inodes_sb+0x1bb/0xa10 fs/fs-writeback.c:2834 sync_filesystem+0x17a/0x230 fs/sync.c:64 generic_shutdown_super+0x6f/0x2c0 fs/super.c:622 kill_block_super+0x44/0x90 fs/super.c:1723 deactivate_locked_super+0xb9/0x130 fs/super.c:474 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1375 task_work_run+0x1d1/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe59918ebe9 RSP: 002b:00007ffde8d7bc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fe599211c65 RCX: 00007fe59918ebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 000000000000000c R08: 00007ffde8d79a16 R09: 00007ffde8d7cf30 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffde8d7cf30 R13: 00007fe599211c05 R14: 00005555944f04a8 R15: 00007ffde8d7e000 INFO: lockdep is turned off. NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: IPVS: lblc: UDP 224.0.0.2:0 - no destination available NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31204 Comm: segctord Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:407 Code: 52 6d fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 6c 0d d1 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1 RSP: 0018:ffffc900000068b0 EFLAGS: 00000002 RAX: 0000000000000038 RBX: 0000000000000038 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020 RBP: 00000000000003f8 R08: ffff888024bb8237 R09: 1ffff11004977046 R10: dffffc0000000000 R11: ffffffff855254e0 R12: dffffc0000000000 R13: ffffffff99d0d8c8 R14: ffffffff9a001f40 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125a08000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe0823ce38 CR3: 000000007723c000 CR4: 00000000003526f0 Call Trace: serial_port_out include/linux/serial_core.h:811 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline] serial8250_console_write+0x1410/0x1ba0 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x725/0xc40 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xc4/0x270 kernel/printk/printk.c:3325 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450 _printk+0xcf/0x120 kernel/printk/printk.c:2475 ip_vs_lblc_schedule+0x61d/0x12e0 net/netfilter/ipvs/ip_vs_lblc.c:514 ip_vs_sched_persist net/netfilter/ipvs/ip_vs_core.c:353 [inline] ip_vs_schedule+0xbaa/0x1c80 net/netfilter/ipvs/ip_vs_core.c:508 udp_conn_schedule+0x332/0x710 net/netfilter/ipvs/ip_vs_proto_udp.c:78 ip_vs_try_to_schedule net/netfilter/ipvs/ip_vs_core.c:1482 [inline] ip_vs_in_hook+0xc06/0x1be0 net/netfilter/ipvs/ip_vs_core.c:2054 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook+0x217/0x380 include/linux/netfilter.h:273 __ip_local_out+0x4db/0x600 net/ipv4/ip_output.c:118 ip_local_out+0x26/0x70 net/ipv4/ip_output.c:127 iptunnel_xmit+0x592/0xa40 net/ipv4/ip_tunnel_core.c:84 udp_tunnel_xmit_skb+0x26e/0x3c0 net/ipv4/udp_tunnel_core.c:192 tipc_udp_xmit+0x7bd/0xaa0 net/tipc/udp_media.c:198 tipc_bearer_xmit_skb+0x2b3/0x400 net/tipc/bearer.c:575 tipc_disc_timeout+0x580/0x6d0 net/tipc/discover.c:338 call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747 expire_timers kernel/time/timer.c:1798 [inline] __run_timers kernel/time/timer.c:2372 [inline] __run_timer_base+0x61a/0x860 kernel/time/timer.c:2384 run_timer_base kernel/time/timer.c:2393 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403 handle_softirqs+0x283/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:747 Code: c7 c7 a0 ed 33 8e e8 df 05 5c 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 53 65 ff 05 30 21 1b 11 e8 1b 03 d7 09 89 RSP: 0018:ffffc9000bd46fe8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffffff90554601 RCX: ffffc9000bd47e88 RDX: ffffc9000bd47101 RSI: ffffffff8172c195 RDI: ffffffff8e339f20 RBP: dffffc0000000000 R08: ffffc9000bd47e70 R09: 0000000000000000 R10: ffffc9000bd47178 R11: fffff520017a8e31 R12: ffffc9000bd47e80 R13: ffffffff8172c195 R14: ffffffff8e339f20 R15: ffffffff8172c195 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x4b/0x3e0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4782 nilfs_segbuf_free fs/nilfs2/segbuf.c:57 [inline] nilfs_truncate_logs+0x174/0x1c0 fs/nilfs2/segbuf.c:287 nilfs_destroy_logs fs/nilfs2/segbuf.h:169 [inline] nilfs_segctor_abort_construction+0xd20/0xdd0 fs/nilfs2/segment.c:1884 nilfs_segctor_do_construct+0x60df/0x6a40 fs/nilfs2/segment.c:2186 nilfs_segctor_construct+0x17b/0x690 fs/nilfs2/segment.c:2462 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2570 [inline] nilfs_segctor_thread+0x6f7/0xe00 fs/nilfs2/segment.c:2684 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 IPVS: lblc: UDP 224.0.0.2:0 - no destination available