INFO: task syz.1.2313:15527 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.2313 state:D stack:27208 pid:15527 tgid:15526 ppid:5851 task_flags:0x400040 flags:0x10080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 relay_open+0x3b8/0x920 kernel/relay.c:516 do_blk_trace_setup+0x561/0x980 kernel/trace/blktrace.c:572 compat_blk_trace_setup kernel/trace/blktrace.c:649 [inline] blk_trace_ioctl+0x35b/0x430 kernel/trace/blktrace.c:717 compat_blkdev_ioctl+0x442/0x780 block/ioctl.c:754 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __ia32_compat_sys_ioctl+0x543/0x840 fs/ioctl.c:638 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf70ce539 RSP: 002b:00000000f54be55c EFLAGS: 00000206 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00000000c0401273 RDX: 0000000080000080 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 5 locks held by kworker/1:0/24: 1 lock held by khungtaskd/31: #0: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5604: #0: ffff8880300a60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by syz.2.2312/15522: 2 locks held by syz.1.2313/15527: #0: ffff888024f4eb48 (&q->debugfs_mutex){+.+.}-{4:4}, at: compat_blk_trace_setup kernel/trace/blktrace.c:648 [inline] #0: ffff888024f4eb48 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_ioctl+0x33f/0x430 kernel/trace/blktrace.c:717 #1: ffffffff8dd8e9a8 (relay_channels_mutex){+.+.}-{4:4}, at: relay_open+0x3b8/0x920 kernel/relay.c:516 2 locks held by syz.4.2446/16049: #0: ffff8880253b6b48 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0xfb/0x1f0 kernel/trace/blktrace.c:613 #1: ffffffff8dd8e9a8 (relay_channels_mutex){+.+.}-{4:4}, at: relay_open+0x3b8/0x920 kernel/relay.c:516 3 locks held by kworker/u8:7/16336: #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc900055dfbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc900055dfbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 2 locks held by syz.0.2745/17250: #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436 #1: ffffffff8dd403f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #1: ffffffff8dd403f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957 1 lock held by syz.3.2747/17254: #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436 2 locks held by syz.3.2747/17259: #0: ffff88807a57e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffff88807a57e130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: tty_write_lock drivers/tty/tty_io.c:939 [inline] #1: ffff88807a57e130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: iterate_tty_write drivers/tty/tty_io.c:958 [inline] #1: ffff88807a57e130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: file_tty_write+0x211/0xa20 drivers/tty/tty_io.c:1081 4 locks held by syz.5.2749/17260: #0: ffff888055eef508 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:979 [inline] #0: ffff888055eef508 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release net/socket.c:648 [inline] #0: ffff888055eef508 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1442 #1: ffffffff8f132d70 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x54/0x90 kernel/notifier.c:379 #2: ffff8880574348d8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nft_rcv_nl_event+0x116/0x640 net/netfilter/nf_tables_api.c:12096 #3: ffffffff8dd403f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #3: ffffffff8dd403f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957 1 lock held by syz.6.2750/17267: #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x83c/0x1150 net/core/dev_ioctl.c:864 1 lock held by syz.6.2750/17268: #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x7a4/0x1150 net/core/dev_ioctl.c:837 1 lock held by syz.6.2750/17269: #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f0cf108 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x7a4/0x1150 net/core/dev_ioctl.c:837 ============================================= 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 08/18/2025 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:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 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: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 10369 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400 Code: e8 fe b2 b1 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ff 5c 16 fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07 RSP: 0018:ffffc90000006730 EFLAGS: 00000002 RAX: 1ffffffff3312a00 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffffff99895290 R08: ffff8880245c8237 R09: 1ffff110048b9046 R10: dffffc0000000000 R11: ffffffff850cc2a0 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff99895000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126372000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000c3accd4 CR3: 000000000db36000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 00000000fee0000e DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:137 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline] wait_for_lsr+0x19e/0x2f0 drivers/tty/serial/8250/8250_port.c:1984 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3288 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3311 [inline] serial8250_console_write+0x134c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3396 console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x728/0xc40 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_dh_schedule+0x268/0x3a0 net/netfilter/ipvs/ip_vs_dh.c:227 ip_vs_schedule+0xa07/0x1c80 net/netfilter/ipvs/ip_vs_core.c:528 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+0xc09/0x1be0 net/netfilter/ipvs/ip_vs_core.c:2054 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc2/0x220 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_crypto_xmit+0x1a1f/0x23a0 net/tipc/crypto.c:1721 tipc_bearer_xmit_skb+0x245/0x400 net/tipc/bearer.c:572 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:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:235 Code: 58 16 00 00 83 fa 02 75 21 48 8b 91 60 16 00 00 48 8b 32 48 8d 7e 01 8b 89 5c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 4e f7 7b 09 cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 RSP: 0018:ffffc9001c987658 EFLAGS: 00000293 RAX: ffffffff81b306bb RBX: 1ffff11017127f61 RCX: ffff88802e493c80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9001c9877e0 R08: ffffffff8f5cd637 R09: 1ffffffff1eb9ac6 R10: dffffc0000000000 R11: fffffbfff1eb9ac7 R12: ffff8880b893fb08 R13: dffffc0000000000 R14: ffff8880b883b1c0 R15: 0000000000000001 csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xd4b/0x12d0 kernel/smp.c:877 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_disable_cpuslocked+0xc5/0x1b0 kernel/jump_label.c:240 static_key_disable+0x1a/0x20 kernel/jump_label.c:248 toggle_allocation_gate+0x1a1/0x240 mm/kfence/core.c:855 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245