INFO: task syz-executor:17529 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22144 pid:17529 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 kernfs_fop_write_iter+0x379/0x4c0 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x712/0xd00 fs/read_write.c:594 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f8d847531ff RSP: 002b:00007ffc6b5d3b40 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f8d847531ff RDX: 0000000000000001 RSI: 00007ffc6b5d3b90 RDI: 0000000000000005 RBP: 00007f8d847da2cb R08: 0000000000000000 R09: 00007ffc6b5d3997 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007ffc6b5d3b90 R14: 00007f8d854d9620 R15: 0000000000000003 Showing all locks held in the system: 3 locks held by kworker/u4:0/9: 1 lock held by khungtaskd/27: #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 7 locks held by kworker/u4:1/144: #0: ffff8880169cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc900010afd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffffffff8d226b10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:589 #3: ffffffff8d257e48 (devlink_mutex){+.+.}-{3:3}, at: devlink_pernet_pre_exit+0x97/0x300 net/core/devlink.c:11534 #4: ffff88801af88658 (&nsim_bus_dev->nsim_bus_reload_lock){+.+.}-{3:3}, at: nsim_dev_reload_down+0x57/0x160 drivers/net/netdevsim/dev.c:870 #5: ffff88801af8f400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1359 [inline] #5: ffff88801af8f400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_reload_destroy+0x115/0x240 drivers/net/netdevsim/dev.c:1561 #6: ffffffff8c1210b0 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4b0 kernel/rcu/tree.c:4043 3 locks held by kworker/u4:3/155: #0: ffff888016879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90002057d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251 2 locks held by getty/3949: #0: ffff88814cbc4098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158 3 locks held by kworker/0:8/4269: #0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc900033dfd00 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff88801af8f400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x56/0xb40 drivers/net/netdevsim/dev.c:757 3 locks held by kworker/u4:16/7380: 2 locks held by kworker/1:12/7662: #0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc9000394fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 6 locks held by syz-executor/17526: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff888060bd7c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 #4: ffff8880518fb178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline] #4: ffff8880518fb178 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1044 [inline] #4: ffff8880518fb178 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb0/0x750 drivers/base/dd.c:1259 #5: ffffffff8d257e48 (devlink_mutex){+.+.}-{3:3}, at: devlink_unregister+0x92/0x1d0 net/core/devlink.c:8984 4 locks held by syz-executor/17529: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff8880283fa088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17649: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff888071389488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17663: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff88804efca488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17671: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff88805f354888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17679: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff888061d81488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17687: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff88804c954c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17695: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff888062436488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17703: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff88804fd8b088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17711: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff88804458c088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17719: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff88805f7edc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17724: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff8880603e7488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17735: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff88805e93b488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 4 locks held by syz-executor/17743: #0: ffff88802c776460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590 #1: ffff88802f7b1c88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287 #2: ffff8880230de748 (kn->active#296){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288 #3: ffffffff8cb72648 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x380 drivers/net/netdevsim/bus.c:344 2 locks held by syz-executor/17751: #0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7a5/0xe90 net/core/rtnetlink.c:5681 #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe0f/0xe50 kernel/hung_task.c:369 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 Code: e8 ab cb 02 f8 e8 a6 cb 02 f8 48 c7 c7 20 c7 11 8c 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 68 65 00 75 89 e8 66 f9 e6 f7 <48> 83 c4 08 c3 90 e8 7b cb 02 f8 e8 76 cb 02 f8 48 c7 c7 20 c7 11 RSP: 0018:ffffc90000d367b0 EFLAGS: 00000246 RAX: e612b45be4d77600 RBX: ffff88807eb6dad8 RCX: e612b45be4d77600 RDX: 0000000000000000 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800 RBP: ffffc90000d36910 R08: dffffc0000000000 R09: fffffbfff1ff5419 R10: fffffbfff1ff5419 R11: 1ffffffff1ff5418 R12: ffff88807b324c80 R13: ffff888062458f88 R14: 0000000000000001 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1a9e6e6e9c CR3: 000000007dd44000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_read_lock include/linux/rcupdate.h:740 [inline] batadv_choose_next_candidate net/batman-adv/distributed-arp-table.c:582 [inline] batadv_dat_select_candidates net/batman-adv/distributed-arp-table.c:654 [inline] batadv_dat_forward_data+0x2e7/0xe80 net/batman-adv/distributed-arp-table.c:685 batadv_interface_tx+0xcd8/0x1410 net/batman-adv/soft-interface.c:330 __netdev_start_xmit include/linux/netdevice.h:5036 [inline] netdev_start_xmit include/linux/netdevice.h:5050 [inline] xmit_one net/core/dev.c:3649 [inline] dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3665 __dev_queue_xmit+0x19df/0x2ed0 net/core/dev.c:4288 br_dev_queue_push_xmit+0x685/0x820 net/bridge/br_forward.c:53 NF_HOOK+0x2e0/0x370 include/linux/netfilter.h:302 br_forward_finish+0x74/0x80 net/bridge/br_forward.c:66 br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:-1 [inline] br_nf_forward_finish+0x986/0xd20 net/bridge/br_netfilter_hooks.c:662 NF_HOOK+0x590/0x610 include/linux/netfilter.h:302 br_nf_forward_arp+0x5da/0xb20 net/bridge/br_netfilter_hooks.c:772 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline] nf_hook_slow+0xb9/0x200 net/netfilter/core.c:584 nf_hook include/linux/netfilter.h:257 [inline] NF_HOOK+0x1eb/0x370 include/linux/netfilter.h:300 __br_forward+0x41f/0x600 net/bridge/br_forward.c:115 br_handle_frame_finish+0x1018/0x12c0 net/bridge/br_input.c:180 nf_hook_bridge_pre net/bridge/br_input.c:264 [inline] br_handle_frame+0xaaf/0x1180 net/bridge/br_input.c:384 __netif_receive_skb_core+0xfb0/0x35d0 net/core/dev.c:5419 __netif_receive_skb_one_core net/core/dev.c:5523 [inline] __netif_receive_skb+0x74/0x290 net/core/dev.c:5639 process_backlog+0x364/0x780 net/core/dev.c:6516 __napi_poll+0xc0/0x430 net/core/dev.c:7075 napi_poll net/core/dev.c:7142 [inline] net_rx_action+0x4a8/0x9c0 net/core/dev.c:7232 handle_softirqs+0x328/0x820 kernel/softirq.c:576 run_ksoftirqd+0x98/0xf0 kernel/softirq.c:943 smpboot_thread_fn+0x4f6/0x970 kernel/smpboot.c:164 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287