INFO: task syz-executor:26822 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22600 pid:26822 tgid:26822 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] schedule+0x164/0x360 kernel/sched/core.c:7005 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7062 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4ef7f5cfce RSP: 002b:00007ffc233a7138 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055558c3eb500 RCX: 00007f4ef7f5cfce RDX: 0000000000000001 RSI: 00007ffc233a71c0 RDI: 0000000000000005 RBP: 00007f4ef803351c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc233a71c0 R14: 00007f4ef8d44620 R15: 0000000000000003 Showing all locks held in the system: 1 lock held by khungtaskd/32: #0: ffffffff8e75e460 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75e460 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75e460 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5574: #0: ffff888036a120a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000331e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 5 locks held by kworker/u8:6/23945: #0: ffff88801b6d6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff88801b6d6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc900042f7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc900042f7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffffffff8fbbf130 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:675 #3: ffff8880363b9528 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_destruct+0x116/0x310 drivers/net/wireguard/device.c:249 #4: ffffffff8e7645c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by kworker/1:9/23970: 1 lock held by syz-executor/26787: #0: ffffffff8e7645c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 4 locks held by syz-executor/26822: #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88807b606c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f4422a8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 7 locks held by syz-executor/26829: 4 locks held by syz-executor/27139: #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff888054928088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f4422a8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/27144: #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff888063fbc088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f4422a8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/27150: #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff8880268b3c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f4422a8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/27167: #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88807eba9488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f4422a8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/27180: #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff888056c70c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f4422a8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/27244: #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff888037f87088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f4422a8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/27387: #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff8880342be420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff888053f5a488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802901db48 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f4422a8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 23970 Comm: kworker/1:9 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: events_long defense_work_handler RIP: 0010:ipt_do_table+0x1416/0x1630 net/ipv4/netfilter/ip_tables.c:362 Code: 24 20 01 00 00 0e 36 e0 45 4a c7 04 3b 00 00 00 00 42 c7 44 3b 08 00 00 00 00 65 48 8b 0d e2 c1 e3 08 48 3b 8c 24 80 01 00 00 <0f> 85 63 01 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 ac RSP: 0018:ffffc90000a08780 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 1ffff92000141114 RCX: a891f7d8d07f5900 RDX: 0000000000000002 RSI: ffffffff8def6963 RDI: ffffffff8c27bd00 RBP: ffffc90000a08960 R08: ffffffff901199b7 R09: 1ffffffff2023336 R10: dffffc0000000000 R11: fffffbfff2023337 R12: ffff8880569a4150 R13: ffff88804149fbc0 R14: 0000000000000001 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125560000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f91bad7f7d0 CR3: 000000000e54c000 CR4: 0000000000350ef0 Call Trace: nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6164 [inline] __netif_receive_skb net/core/dev.c:6277 [inline] process_backlog+0xaa3/0x1950 net/core/dev.c:6628 __napi_poll+0xae/0x340 net/core/dev.c:7692 napi_poll net/core/dev.c:7755 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7912 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] update_defense_level+0x91e/0xd70 net/netfilter/ipvs/ip_vs_ctl.c:209 defense_work_handler+0x2d/0xd0 net/netfilter/ipvs/ip_vs_ctl.c:234 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245