INFO: task syz-executor:6743 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:21464 pid:6743 tgid:6743 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7307 rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline] rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline] mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547 lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 jfs_umount+0x2ef/0x3c0 fs/jfs/jfs_umount.c:114 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194 generic_shutdown_super+0x135/0x2c0 fs/super.c:642 kill_block_super+0x44/0x90 fs/super.c:1722 deactivate_locked_super+0xb9/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd8491101f7 RSP: 002b:00007fff1f8dcb98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fd849191d7d RCX: 00007fd8491101f7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff1f8dcc50 RBP: 00007fff1f8dcc50 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff1f8ddce0 R13: 00007fd849191d7d R14: 000000000002fb0c R15: 00007fff1f8ddd20 INFO: task syz-executor:7055 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:21384 pid:7055 tgid:7055 ppid:1 task_flags:0x400140 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7307 rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline] rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline] mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547 lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 jfs_umount+0x2ef/0x3c0 fs/jfs/jfs_umount.c:114 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194 generic_shutdown_super+0x135/0x2c0 fs/super.c:642 kill_block_super+0x44/0x90 fs/super.c:1722 deactivate_locked_super+0xb9/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f79c23e01f7 RSP: 002b:00007fff0492bc98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f79c2461d7d RCX: 00007f79c23e01f7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff0492bd50 RBP: 00007fff0492bd50 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff0492cde0 R13: 00007f79c2461d7d R14: 0000000000032ed0 R15: 00007fff0492ce20 Showing all locks held in the system: 3 locks held by kworker/u8:0/12: #0: ffff88814d21f938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88814d21f938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90000117bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90000117bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x119/0x15a0 net/ipv6/addrconf.c:4194 1 lock held by khungtaskd/38: #0: ffffffff8d3aa400 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d3aa400 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8d3aa400 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:2/43: 3 locks held by kworker/u8:5/143: #0: ffff88813ff29938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88813ff29938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc900039dfbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc900039dfbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 2 locks held by dhcpcd/5476: #0: ffffffff8e64c218 (vlan_ioctl_mutex){+.+.}-{4:4}, at: sock_ioctl+0x5f1/0x790 net/socket.c:1337 #1: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: vlan_ioctl_handler+0xd0/0x650 net/8021q/vlan.c:577 2 locks held by getty/5568: #0: ffff88823bf400a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222 2 locks held by syz-executor/5815: #0: ffff8880309940d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880309940d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880309940d0 (&type->s_umount_key#93){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8d7e0e38 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/5831: #0: ffff88802c2140d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88802c2140d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88802c2140d0 (&type->s_umount_key#93){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8d7e0e38 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/6743: #0: ffff8880295160d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880295160d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880295160d0 (&type->s_umount_key#93){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8d7e0e38 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/7055: #0: ffff88802f93a0d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88802f93a0d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88802f93a0d0 (&type->s_umount_key#93){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8d7e0e38 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 1 lock held by syz.2.264/7947: #0: ffff88802c2140d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff88802c2140d0 (&type->s_umount_key#93){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz-executor/8799: #0: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x5b7/0xd20 net/ipv6/addrconf.c:5027 7 locks held by syz-executor/8833: #0: ffff88801041c480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3110 [inline] #0: ffff88801041c480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682 #1: ffff88807f2a3878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 #2: ffff888026b25a58 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888026b25a58 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344 #3: ffffffff8dedd938 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x12c/0x6f0 drivers/net/netdevsim/bus.c:184 #4: ffff888035a750d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #4: ffff888035a750d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006 #5: ffff88805d9b8300 (&devlink->lock_key#22){+.+.}-{4:4}, at: nsim_drv_probe+0xc2/0xba0 drivers/net/netdevsim/dev.c:1582 #6: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1040 [inline] #6: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_create+0x800/0xf20 drivers/net/netdevsim/netdev.c:1134 4 locks held by syz-executor/8842: #0: ffff88801041c480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3110 [inline] #0: ffff88801041c480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682 #1: ffff888038e6b878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 #2: ffff888026b25a58 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888026b25a58 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344 #3: ffffffff8dedd938 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x12c/0x6f0 drivers/net/netdevsim/bus.c:184 1 lock held by syz-executor/8911: #0: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064 2 locks held by syz-executor/8919: #0: ffffffff8eb78a90 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8eb78a90 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8eb78a90 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8e667db8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 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:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:158 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: 43 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: netns cleanup_net RIP: 0010:__lock_acquire+0xac6/0xd20 kernel/locking/lockdep.c:5241 Code: c0 48 8b 3c 24 48 83 78 40 00 0f 84 6a 01 00 00 4c 89 f6 89 ea 4c 89 f9 e8 27 38 00 00 85 c0 0f 84 e4 01 00 00 41 f6 46 22 10 <75> 2e 48 8b 1c 24 4c 89 bb 50 0b 00 00 8b 83 58 0b 00 00 ff c0 89 RSP: 0018:ffffc90000b47150 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000006 RCX: 020d96885d1ded00 RDX: 0000000000000000 RSI: ffff8881436d2a50 RDI: ffff8881436d1e00 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8ab78e00 R10: dffffc0000000000 R11: fffffbfff1d6bbc7 R12: 00000000ef0d8e59 R13: ffff8881436d2960 R14: ffff8881436d2a50 R15: 67c03d540fb62ed3 FS: 0000000000000000(0000) GS:ffff888127020000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f000e730e9c CR3: 000000000d1a6000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 rwbase_write_lock+0x180/0x750 kernel/locking/rwbase_rt.c:252 __kernfs_remove+0x39a/0x570 fs/kernfs/dir.c:1519 kernfs_remove_by_name_ns+0xaf/0x130 fs/kernfs/dir.c:1717 kernfs_remove_by_name include/linux/kernfs.h:633 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xfc/0x2c0 fs/sysfs/group.c:322 sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:346 device_remove_groups drivers/base/core.c:2843 [inline] device_remove_attrs+0x1aa/0x260 drivers/base/core.c:2973 device_del+0x50d/0x8e0 drivers/base/core.c:3877 unregister_netdevice_many_notify+0x1a57/0x1fe0 net/core/dev.c:12289 unregister_netdevice_many net/core/dev.c:12317 [inline] default_device_exit_batch+0x819/0x890 net/core/dev.c:12821 ops_exit_list net/core/net_namespace.c:205 [inline] ops_undo_list+0x525/0x990 net/core/net_namespace.c:252 cleanup_net+0x4de/0x820 net/core/net_namespace.c:695 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245