INFO: task syz-executor:4443 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:22608 pid:4443 tgid:4443 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821 new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0a3b55e68e RSP: 002b:00007fff0c7ccf88 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055556fcf2500 RCX: 00007f0a3b55e68e RDX: 0000000000000003 RSI: 00007fff0c7cd010 RDI: 0000000000000005 RBP: 00007f0a3b634716 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007fff0c7cd010 R14: 00007f0a3c354620 R15: 0000000000000003 INFO: task syz-executor:4461 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:22824 pid:4461 tgid:4461 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821 del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fac8ab5e68e RSP: 002b:00007ffcb4176198 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000555555dde500 RCX: 00007fac8ab5e68e RDX: 0000000000000001 RSI: 00007ffcb4176220 RDI: 0000000000000005 RBP: 00007fac8ac346f2 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffcb4176220 R14: 00007fac8b954620 R15: 0000000000000003 Showing all locks held in the system: 1 lock held by ksoftirqd/1/23: #0: ffff8880b873b160 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:667 1 lock held by khungtaskd/31: #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5382: #0: ffff888032e5d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 5 locks held by kworker/u8:22/7861: 4 locks held by syz-executor/4443: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff88807fdaa480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803d28 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803d28 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184 4 locks held by syz-executor/4461: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff888021b2f480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 7 locks held by syz-executor/4465: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff88804e41b080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 #4: ffff88807bac9128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #4: ffff88807bac9128 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline] #4: ffff88807bac9128 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369 #5: ffff888051f2f258 (&devlink->lock_key#7){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1799 #6: ffffffff8eb5fe38 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857 3 locks held by syz-executor/4469: #0: ffff88805c84cea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:497 [inline] #0: ffff88805c84cea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x22a/0x5b0 net/bluetooth/hci_core.c:2678 #1: ffff88805c84c0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x61f/0x10a0 net/bluetooth/hci_sync.c:5393 #2: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #2: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961 4 locks held by syz-executor/4477: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff888033d97c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803d28 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803d28 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184 4 locks held by syz-executor/4868: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff888056688080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/4934: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff8880338ef080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/4942: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff8880733c6080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/4968: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff88807985dc80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/5628: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff888056ebc080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/5649: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff8880362b7080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/5652: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff88807ef84480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/5686: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff888069190880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/5712: #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #0: ffff888036b56450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #1: ffff888076325c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336 #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff888029803c38 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337 #3: ffffffff8f8a8a20 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [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:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 7c 80 02 e9 13 05 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 5a 1a 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc90000197e40 EFLAGS: 00000246 RAX: 000000000023e1af RBX: ffffffff819ab450 RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8e22a5a0 RDI: ffffffff8c4bd380 RBP: ffffc90000197f10 R08: ffff8880b87338db R09: 1ffff110170e671b R10: dffffc0000000000 R11: ffffed10170e671c R12: 0000000000000000 R13: 1ffff11003c50000 R14: 1ffff92000032fd0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125058000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055fd0f572a38 CR3: 000000003578e000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:767 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:768 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x2e0/0x540 kernel/sched/idle.c:355 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x157