INFO: task syz-executor:6880 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:22128 pid:6880 tgid:6880 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16d8/0x55e0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7564 rt_mutex_slowlock_block+0x55f/0x690 kernel/locking/rtmutex.c:1665 __rt_mutex_slowlock kernel/locking/rtmutex.c:1742 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1782 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1822 __rt_mutex_lock kernel/locking/rtmutex.c:1837 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:553 lmLogClose+0xad/0x530 fs/jfs/jfs_logmgr.c:1441 jfs_umount+0x2da/0x3b0 fs/jfs/jfs_umount.c:124 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646 kill_block_super+0x44/0x90 fs/super.c:1725 deactivate_locked_super+0xbc/0x130 fs/super.c:476 cleanup_mnt+0x3d3/0x460 fs/namespace.c:1312 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0x193/0x6b0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f32d7cbe097 RSP: 002b:00007ffd670499b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f32d7d521ca RCX: 00007f32d7cbe097 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd67049a70 RBP: 00007ffd67049a70 R08: 00007ffd6704aa70 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd6704ab00 R13: 00007f32d7d521ca R14: 00000000000392af R15: 00007ffd6704ab40 INFO: task syz.8.159:7289 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.159 state:D stack:25424 pid:7289 tgid:7288 ppid:6520 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16d8/0x55e0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7564 rt_mutex_slowlock_block+0x55f/0x690 kernel/locking/rtmutex.c:1665 __rt_mutex_slowlock kernel/locking/rtmutex.c:1742 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1782 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1822 __rt_mutex_lock kernel/locking/rtmutex.c:1837 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:553 lmLogClose+0xad/0x530 fs/jfs/jfs_logmgr.c:1441 jfs_umount+0x2da/0x3b0 fs/jfs/jfs_umount.c:124 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646 kill_block_super+0x44/0x90 fs/super.c:1725 deactivate_locked_super+0xbc/0x130 fs/super.c:476 cleanup_mnt+0x3d3/0x460 fs/namespace.c:1312 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0x193/0x6b0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f07bc51e0ca RSP: 002b:00007f07ba775e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffea RBX: 00007f07ba775ee0 RCX: 00007f07bc51e0ca RDX: 00002000000000c0 RSI: 0000200000000000 RDI: 00007f07ba775ea0 RBP: 00002000000000c0 R08: 00007f07ba775ee0 R09: 000000000001c802 R10: 000000000001c802 R11: 0000000000000246 R12: 0000200000000000 R13: 00007f07ba775ea0 R14: 0000000000005f97 R15: 00002000000022c0 Showing all locks held in the system: 4 locks held by kworker/u8:1/13: #0: ffff88801aac8938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801aac8938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #2: ffffffff8f139760 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:673 #3: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] #3: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x28e/0x8d0 net/core/net_namespace.c:248 1 lock held by khungtaskd/37: #0: ffffffff8ddc7b60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8ddc7b60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8ddc7b60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:8/825: #0: ffff888019c34138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff888019c34138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc900052bfc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc900052bfc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #2: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 4 locks held by kworker/u8:9/830: 3 locks held by kworker/u8:13/3295: #0: ffff888031cd4138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff888031cd4138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc9000e52fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc9000e52fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #2: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x123/0x16e0 net/ipv6/addrconf.c:4208 2 locks held by dhcpcd/5268: #0: ffff888025924928 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xe7/0xee0 net/netlink/af_netlink.c:2272 #1: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6865 2 locks held by getty/5363: #0: ffff8880369130a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cb62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1390 drivers/tty/n_tty.c:2211 2 locks held by syz-executor/5611: #0: ffff888029c6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff888029c6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff888029c6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 #1: ffffffff8e256938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xad/0x530 fs/jfs/jfs_logmgr.c:1441 3 locks held by kworker/0:4/5621: #0: ffff88813fe33938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88813fe33938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc90004d7fc40 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc90004d7fc40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #2: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/1:5/5727: #0: ffff88813fe33938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88813fe33938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc9000592fc40 (rx_mode_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc9000592fc40 (rx_mode_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #2: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: netdev_rx_mode_work+0x19/0x450 net/core/dev_addr_lists.c:1312 2 locks held by syz-executor/6880: #0: ffff8880782700d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880782700d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff8880782700d0 (&type->s_umount_key#60){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 #1: ffffffff8e256938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xad/0x530 fs/jfs/jfs_logmgr.c:1441 2 locks held by syz.8.159/7289: #0: ffff888029b6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff888029b6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff888029b6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 #1: ffffffff8e256938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xad/0x530 fs/jfs/jfs_logmgr.c:1441 2 locks held by syz-executor/7436: #0: ffff888024de60d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff888024de60d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff888024de60d0 (&type->s_umount_key#60){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 #1: ffffffff8e256938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xad/0x530 fs/jfs/jfs_logmgr.c:1441 1 lock held by syz.2.279/8681: #0: ffff888029c6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff888029c6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 1 lock held by syz.2.279/8721: #0: ffff888029c6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff888029c6a0d0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 1 lock held by syz-executor/8791: #0: ffff888065e1a480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 1 lock held by syz-executor/8833: #0: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4109 1 lock held by syz-executor/8892: #0: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0 net/ipv4/devinet.c:978 1 lock held by syz-executor/8926: #0: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0 net/ipv4/devinet.c:978 7 locks held by syz-executor/9105: #0: ffff888037100480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline] #0: ffff888037100480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:684 #1: ffff88805a678c78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:343 #2: ffff888028d4c2d8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028d4c2d8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:344 #3: ffffffff8e9ce938 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 #4: ffff88805f960160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88805f960160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1174 [inline] #4: ffff88805f960160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1372 #5: ffff8880374d0310 (&devlink->lock_key#14){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1799 #6: ffffffff8f1484b8 (rtnl_mutex){+.+.}-{4:4}, at: unregister_nexthop_notifier+0x17/0x40 net/ipv4/nexthop.c:4021 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(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:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 830 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_unbound idle_cull_fn RIP: 0010:__bfs kernel/locking/lockdep.c:1753 [inline] RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline] RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline] RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline] RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline] RIP: 0010:__lock_acquire+0x17a5/0x2cc0 kernel/locking/lockdep.c:5237 Code: 00 00 0f 83 84 01 00 00 4e 8b 3c e5 00 38 50 95 ff c0 25 ff 0f 00 00 89 05 58 b6 b0 13 4d 85 ff 0f 84 ac 01 00 00 49 8b 47 10 <48> 85 c0 0f 84 18 0d 00 00 8b 0d 44 b6 b0 13 39 48 5c 0f 84 6a ff RSP: 0018:ffffc900052ef4e0 EFLAGS: 00000086 RAX: ffffffff92fad4f0 RBX: 00000000000003cd RCX: ffffffff95f76e48 RDX: ffffffff92f7fb70 RSI: ffff888025678c98 RDI: 00000000000003cd RBP: 968d930a955ca3ba R08: ffffc900052ef4a8 R09: 0000000000000020 R10: 0000000000000000 R11: ffffffff81a054b0 R12: 00000000000005d9 R13: ffff888025678c98 R14: ffff888025678000 R15: ffffffff95f76e48 FS: 0000000000000000(0000) GS:ffff8881263a1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001000 CR3: 0000000040e9a000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 do_write_seqcount_begin_nested include/linux/seqlock.h:478 [inline] do_write_seqcount_begin include/linux/seqlock.h:504 [inline] psi_write_begin+0xab/0x160 kernel/sched/psi.c:183 psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933 psi_sched_switch kernel/sched/stats.h:225 [inline] __schedule+0x28e9/0x55e0 kernel/sched/core.c:7183 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline] _raw_spin_unlock_irq+0x45/0x50 kernel/locking/spinlock.c:206 idle_cull_fn+0x353/0x740 kernel/workqueue.c:3029 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478 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