INFO: task kworker/u8:11:14529 blocked for more than 143 seconds. Not tainted 6.16.0-rc2-syzkaller-00047-g52da431bf03b #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:11 state:D stack:21160 pid:14529 tgid:14529 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 afs_cell_purge+0x3d9/0x540 fs/afs/cell.c:893 afs_net_exit+0x50/0x100 fs/afs/main.c:147 ops_exit_list net/core/net_namespace.c:200 [inline] ops_undo_list+0x49a/0x990 net/core/net_namespace.c:253 cleanup_net+0x4c5/0x800 net/core/net_namespace.c:686 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e13eda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13eda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13eda0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770 2 locks held by kworker/u8:3/49: 5 locks held by kworker/1:2/3085: #0: ffff888021ac0548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888021ac0548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000c077bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000c077bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffff88823be7c998 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline] #2: ffff88823be7c998 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a00 drivers/usb/core/hub.c:5863 #3: ffff88805835d198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline] #3: ffff88805835d198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1004 #4: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #4: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #4: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: __queue_work+0x103/0xfe0 kernel/workqueue.c:2261 2 locks held by getty/5600: #0: ffff88814c3820a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 5 locks held by kworker/0:3/5833: #0: ffff888021ac0548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888021ac0548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc900041efbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900041efbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffff88823bebe998 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline] #2: ffff88823bebe998 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a00 drivers/usb/core/hub.c:5863 #3: ffff888145751510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3220 [inline] #3: ffff888145751510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5432 [inline] #3: ffff888145751510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5675 [inline] #3: ffff888145751510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5835 [inline] #3: ffff888145751510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21a3/0x4a00 drivers/usb/core/hub.c:5917 #4: ffff888140fa6368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5433 [inline] #4: ffff888140fa6368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5675 [inline] #4: ffff888140fa6368 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5835 [inline] #4: ffff888140fa6368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21cb/0x4a00 drivers/usb/core/hub.c:5917 3 locks held by kworker/0:5/5908: #0: ffff888021ac0548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888021ac0548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000461fbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000461fbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffff888028d41198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:884 [inline] #2: ffff888028d41198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a00 drivers/usb/core/hub.c:5863 3 locks held by kworker/u8:11/14529: #0: ffff88801b2fe148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801b2fe148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000b887bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000b887bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffffffff8f5036d0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:662 1 lock held by syz-executor/17793: #0: ffffffff8e1448b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #0: ffffffff8e1448b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:998 4 locks held by syz.3.3707/19926: #0: ffffffff8eb221a8 (loop_validate_mutex){+.+.}-{4:4}, at: loop_global_lock_killable drivers/block/loop.c:114 [inline] #0: ffffffff8eb221a8 (loop_validate_mutex){+.+.}-{4:4}, at: loop_change_fd drivers/block/loop.c:552 [inline] #0: ffffffff8eb221a8 (loop_validate_mutex){+.+.}-{4:4}, at: lo_ioctl+0xd94/0x2410 drivers/block/loop.c:1516 #1: ffff888025727400 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_global_lock_killable drivers/block/loop.c:118 [inline] #1: ffff888025727400 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_change_fd drivers/block/loop.c:552 [inline] #1: ffff888025727400 (&lo->lo_mutex){+.+.}-{4:4}, at: lo_ioctl+0x17d6/0x2410 drivers/block/loop.c:1516 #2: ffff8881427b4ee8 (&q->q_usage_counter(io)#22){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:934 [inline] #2: ffff8881427b4ee8 (&q->q_usage_counter(io)#22){++++}-{0:0}, at: loop_change_fd drivers/block/loop.c:585 [inline] #2: ffff8881427b4ee8 (&q->q_usage_counter(io)#22){++++}-{0:0}, at: lo_ioctl+0x1d56/0x2410 drivers/block/loop.c:1516 #3: ffff8881427b4f20 (&q->q_usage_counter(queue)#21){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:934 [inline] #3: ffff8881427b4f20 (&q->q_usage_counter(queue)#21){+.+.}-{0:0}, at: loop_change_fd drivers/block/loop.c:585 [inline] #3: ffff8881427b4f20 (&q->q_usage_counter(queue)#21){+.+.}-{0:0}, at: lo_ioctl+0x1d56/0x2410 drivers/block/loop.c:1516 1 lock held by syz.0.3710/19922: #0: ffffffff8e144780 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3782 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc2-syzkaller-00047-g52da431bf03b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:470 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 18811 Comm: kworker/u8:0 Not tainted 6.16.0-rc2-syzkaller-00047-g52da431bf03b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:391 [inline] RIP: 0010:__rcu_read_lock+0x15/0x60 kernel/rcu/tree_plugin.h:414 Code: 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 53 65 48 8b 1c 25 08 f0 9c 92 48 81 c3 44 04 00 00 <48> 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 RSP: 0018:ffffc90003acfa10 EFLAGS: 00000286 RAX: 1ffff1100537e788 RBX: ffff888026115e44 RCX: ffff888026115a00 RDX: 0000000000000000 RSI: ffffffff8db6ecc7 RDI: ffff888026115a00 RBP: ffff888031a81b20 R08: 0000000000000000 R09: ffffffff8b3418f2 R10: dffffc0000000000 R11: ffffffff8b341820 R12: dffffc0000000000 R13: ffff888029bf3c50 R14: ffff88807e194d80 R15: 0000000000000364 FS: 0000000000000000(0000) GS:ffff888125c51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1708f81178 CR3: 000000006b9f0000 CR4: 00000000003526f0 Call Trace: rcu_read_lock include/linux/rcupdate.h:839 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xcb/0x610 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245