INFO: task syz-executor:17249 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:22344 pid:17249 tgid:17249 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1539/0x5110 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0x164/0x360 kernel/sched/core.c:7004 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061 __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: 0033:0x7f84f815b78e RSP: 002b:00007fff55a86d18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00005555842f8500 RCX: 00007f84f815b78e RDX: 0000000000000001 RSI: 00007fff55a86da0 RDI: 0000000000000005 RBP: 00007f84f8208a88 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fff55a86da0 R14: 00007f84f8f44620 R15: 0000000000000003 Showing all locks held in the system: 3 locks held by ksoftirqd/1/23: 1 lock held by khungtaskd/30: #0: ffffffff8e760160 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e760160 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e760160 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:6/3488: #0: ffff8880317af948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x855/0x1650 kernel/workqueue.c:3254 #1: ffffc9000bb4fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x87c/0x1650 kernel/workqueue.c:3255 #2: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4199 1 lock held by dhcpcd/5484: #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x32b/0x1b30 net/ipv4/devinet.c:1120 2 locks held by getty/5576: #0: ffff8880370840a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 5 locks held by kworker/1:3/5889: 3 locks held by kworker/u8:11/7084: #0: ffff88801b0ac148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x855/0x1650 kernel/workqueue.c:3254 #1: ffffc90003aafc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x87c/0x1650 kernel/workqueue.c:3255 #2: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 5 locks held by kworker/u8:14/14769: #0: ffff88801c2ae948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x855/0x1650 kernel/workqueue.c:3254 #1: ffffc90003e4fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x87c/0x1650 kernel/workqueue.c:3255 #2: ffffffff8fbb7150 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0 net/core/net_namespace.c:670 #3: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] #3: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x2a4/0x940 net/core/net_namespace.c:248 #4: ffffffff8e7662c0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 3 locks held by kworker/0:14/16712: #0: ffff88801b06b548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x1650 kernel/workqueue.c:3254 #1: ffffc9000ae37c40 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x87c/0x1650 kernel/workqueue.c:3255 #2: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 7 locks held by syz-executor/17244: #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88803b52c088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f43a808 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 #4: ffff8880386800e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #4: ffff8880386800e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1106 [inline] #4: ffff8880386800e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x860 drivers/base/dd.c:1304 #5: ffff88802bd40250 (&devlink->lock_key#71){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1779 #6: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #6: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2156 4 locks held by syz-executor/17249: #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff8880b0f76c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f43a808 (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/17386: #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff888099e84088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f43a808 (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/17389: #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88803a93a488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f43a808 (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/17468: #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88804ceb1888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f43a808 (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/17483: #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff888054c50088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f43a808 (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/17491: #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff888033efa420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:684 #1: ffff88805605c088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028f5c878 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f43a808 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 1 lock held by syz-executor/17653: #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/17658: #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/17661: #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/17666: #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/17671: #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/17674: #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 1 lock held by syz-executor/17679: #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8fbc5fc8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 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:347 [inline] watchdog+0x103d/0x1090 kernel/hung_task.c:516 kthread+0x388/0x470 kernel/kthread.c:467 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: 17138 Comm: kworker/1:5 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: wg-crypt-wg0 wg_packet_tx_worker RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data kernel/kcov.c:246 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x17/0x90 kernel/kcov.c:314 Code: 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 28 3f 55 11 65 8b 0d 49 3f 55 11 <81> e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b 83 ba 54 16 00 00 RSP: 0018:ffffc90000a08978 EFLAGS: 00000246 RAX: ffffffff897e12cd RBX: 0000000000000001 RCX: 0000000080000101 RDX: ffff8880b3f7dac0 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000a08c00 R08: ffff8880b3f7dac0 R09: 0000000000000002 R10: 000000000000a888 R11: 0000000000000100 R12: 0000000000000000 R13: dffffc0000000000 R14: 1ffff11011cb7328 R15: ffff888077664c00 FS: 0000000000000000(0000) GS:ffff888125572000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f382c7047e8 CR3: 000000000e54c000 CR4: 00000000003526f0 Call Trace: read_pnet_rcu include/net/net_namespace.h:427 [inline] dev_net_rcu include/linux/netdevice.h:2752 [inline] __netif_receive_skb_core+0x55d/0x30f0 net/core/dev.c:5984 __netif_receive_skb_one_core net/core/dev.c:6150 [inline] __netif_receive_skb net/core/dev.c:6265 [inline] process_backlog+0x76d/0x1950 net/core/dev.c:6617 __napi_poll+0xae/0x340 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7896 handle_softirqs+0x22a/0x870 kernel/softirq.c:626 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] rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline] keep_key_fresh drivers/net/wireguard/send.c:135 [inline] wg_packet_create_data_done drivers/net/wireguard/send.c:259 [inline] wg_packet_tx_worker+0x586/0x7c0 drivers/net/wireguard/send.c:276 process_one_work+0x949/0x1650 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0xb46/0x1140 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 00 90 90 90 90 90 add %dl,-0x6f6f6f70(%rax) 8: 90 nop 9: 90 nop a: 90 nop b: 90 nop c: 90 nop d: 90 nop e: 90 nop f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: f3 0f 1e fa endbr64 17: 48 8b 04 24 mov (%rsp),%rax 1b: 65 48 8b 15 28 3f 55 mov %gs:0x11553f28(%rip),%rdx # 0x11553f4b 22: 11 23: 65 8b 0d 49 3f 55 11 mov %gs:0x11553f49(%rip),%ecx # 0x11553f73 * 2a: 81 e1 00 01 ff 00 and $0xff0100,%ecx <-- trapping instruction 30: 74 11 je 0x43 32: 81 f9 00 01 00 00 cmp $0x100,%ecx 38: 75 5b jne 0x95 3a: 83 .byte 0x83 3b: ba 54 16 00 00 mov $0x1654,%edx