INFO: task syz-executor.4:12076 blocked for more than 143 seconds. Not tainted 6.4.0-rc2-syzkaller-00018-g4d6d4c7f541d #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:24440 pid:12076 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5343 [inline] __schedule+0xc9a/0x5880 kernel/sched/core.c:6669 schedule+0xde/0x1a0 kernel/sched/core.c:6745 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6804 rwsem_down_write_slowpath+0x3e2/0x1220 kernel/locking/rwsem.c:1178 __down_write_common kernel/locking/rwsem.c:1306 [inline] __down_write kernel/locking/rwsem.c:1315 [inline] down_write+0x1d2/0x200 kernel/locking/rwsem.c:1574 unregister_netdevice_notifier+0x22/0x180 net/core/dev.c:1757 devlink_free+0x2cb/0x460 net/devlink/core.c:269 nsim_drv_remove+0x158/0x1d0 drivers/net/netdevsim/dev.c:1687 device_remove+0xc8/0x170 drivers/base/dd.c:567 __device_release_driver drivers/base/dd.c:1272 [inline] device_release_driver_internal+0x443/0x610 drivers/base/dd.c:1295 bus_remove_device+0x22c/0x420 drivers/base/bus.c:574 device_del+0x399/0xa30 drivers/base/core.c:3814 device_unregister+0x1e/0xc0 drivers/base/core.c:3844 nsim_bus_dev_del drivers/net/netdevsim/bus.c:310 [inline] del_device_store+0x34e/0x4a0 drivers/net/netdevsim/bus.c:219 bus_attr_store+0x76/0xa0 drivers/base/bus.c:170 sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x3f1/0x600 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:1868 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x945/0xd50 fs/read_write.c:584 ksys_write+0x12b/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f5fc383deef RSP: 002b:00007ffc7bb39850 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f5fc383deef RDX: 0000000000000001 RSI: 00007ffc7bb398a0 RDI: 0000000000000005 RBP: 0000000000000005 R08: 0000000000000000 R09: 00007ffc7bb397f0 R10: 0000000000000000 R11: 0000000000000293 R12: 00007f5fc38e78b6 R13: 00007ffc7bb398a0 R14: 0000000000000000 R15: 00007ffc7bb39f70 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8c795470 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:518 1 lock held by rcu_tasks_trace/13: #0: ffffffff8c795170 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:518 1 lock held by khungtaskd/27: #0: ffffffff8c796080 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6545 2 locks held by getty/4751: #0: ffff88814b884098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x26/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900020482f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef4/0x13e0 drivers/tty/n_tty.c:2176 4 locks held by kworker/u4:3/11713: 6 locks held by syz-executor.4/12076: #0: ffff888023626460 (sb_writers#9){.+.+}-{0:0}, at: ksys_write+0x12b/0x250 fs/read_write.c:637 #1: ffff888016fe2888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x285/0x600 fs/kernfs/file.c:325 #2: ffff888141fba0f0 (kn->active#51){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2a9/0x600 fs/kernfs/file.c:326 #3: ffffffff8d7efb68 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xc9/0x4a0 drivers/net/netdevsim/bus.c:209 #4: ffff88807ee690e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #4: ffff88807ee690e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1095 [inline] #4: ffff88807ee690e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa4/0x610 drivers/base/dd.c:1292 #5: ffffffff8e0f7390 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x22/0x180 net/core/dev.c:1757 1 lock held by syz-executor.4/12127: #0: ffffffff8e0f7390 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4cb/0x8e0 net/core/net_namespace.c:487 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted 6.4.0-rc2-syzkaller-00018-g4d6d4c7f541d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 nmi_cpu_backtrace+0x29c/0x350 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x2a4/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xe16/0x1090 kernel/hung_task.c:379 kthread+0x344/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 11713 Comm: kworker/u4:3 Not tainted 6.4.0-rc2-syzkaller-00018-g4d6d4c7f541d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 Workqueue: netns cleanup_net RIP: 0010:__sanitizer_cov_trace_pc+0x3b/0x70 kernel/kcov.c:207 Code: 81 e1 00 01 00 00 65 48 8b 14 25 00 bc 03 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 0c 16 00 00 85 c0 74 2b 8b 82 e8 15 00 00 <83> f8 02 75 20 48 8b 8a f0 15 00 00 8b 92 ec 15 00 00 48 8b 01 48 RSP: 0018:ffffc900035cfab8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000040000 RCX: 0000000000000000 RDX: ffff888080300040 RSI: ffffffff884dc337 RDI: 0000000000000004 RBP: dffffc0000000000 R08: 0000000000000004 R09: 0000000000031760 R10: 0000000000040000 R11: 0000000000000000 R12: ffffc900035cfb98 R13: 0000000000031760 R14: 0000000000000001 R15: 000000000000fa40 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000558c33d6bcc0 CR3: 000000007e191000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: get_next_corpse net/netfilter/nf_conntrack_core.c:2366 [inline] nf_ct_iterate_cleanup+0xa7/0x500 net/netfilter/nf_conntrack_core.c:2419 nf_ct_iterate_cleanup_net+0xdb/0x110 net/netfilter/nf_conntrack_core.c:2440 nf_conntrack_cleanup_net_list+0x1cc/0x5d0 net/netfilter/nf_conntrack_core.c:2553 ops_exit_list+0x125/0x170 net/core/net_namespace.c:175 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:614 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552 kthread+0x344/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308