INFO: task syz-executor:4189 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:21584 pid: 4189 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:1914 gfs2_gl_hash_clear+0x1ab/0x2f0 fs/gfs2/glock.c:2183 gfs2_put_super+0x769/0x7d0 fs/gfs2/super.c:624 generic_shutdown_super+0x130/0x300 fs/super.c:475 kill_block_super+0x7c/0xe0 fs/super.c:1427 deactivate_locked_super+0x93/0xf0 fs/super.c:335 cleanup_mnt+0x42d/0x4e0 fs/namespace.c:1148 task_work_run+0x125/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fe00ea13117 RSP: 002b:00007fff5602b6b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fe00ea7b71f RCX: 00007fe00ea13117 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff5602b770 RBP: 00007fff5602b770 R08: 00007fff5602c770 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff5602c800 R13: 00007fe00ea7b71f R14: 000000000002a299 R15: 00007fff5602c840 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 5 locks held by kworker/u4:1/144: #0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc9000172fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffffffff8d4308d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589 #3: ffffffff8d43c548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock_unregistering net/core/dev.c:11620 [inline] #3: ffffffff8d43c548 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0x165/0x3c0 net/core/dev.c:11658 #4: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #4: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845 1 lock held by dhcpcd/3852: #0: ffffffff8d43c548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8d43c548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5681 2 locks held by getty/3940: #0: ffff88814c84c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158 3 locks held by kworker/u5:1/4184: #0: ffff888021714138 ((wq_completion)hci8){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc90002e4fd00 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffff888023e84ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_open+0xa4/0x1270 net/bluetooth/hci_core.c:1446 1 lock held by syz-executor/4189: #0: ffff88807b5c60e0 (&type->s_umount_key#79){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365 2 locks held by kworker/0:6/4240: #0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc900042dfd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 4 locks held by kworker/u4:7/4561: #0: ffff888055497138 ((wq_completion)phy31){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc9000326fd00 ((work_completion)(&(&local->scan_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffff8880664929c8 (&local->mtx){+.+.}-{3:3}, at: ieee80211_scan_work+0x51/0x1b40 net/mac80211/scan.c:1074 #3: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #3: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845 3 locks held by kworker/u4:9/4782: #0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc9000132fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffffffff8d43c548 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251 3 locks held by kworker/0:14/5456: #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc9000313fd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffffffff8d43c548 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74 1 lock held by syz.7.1331/9875: #0: ffff88807b5c60e0 (&type->s_umount_key#79){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:716 1 lock held by syz.2.1864/12377: #0: ffff88807b5c60e0 (&type->s_umount_key#79){++++}-{3:3}, at: user_get_super+0x118/0x240 fs/super.c:850 2 locks held by syz-executor/12964: #0: ffff888020d90918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915 #1: ffff888020f22468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xaa/0xb90 drivers/block/loop.c:1366 2 locks held by syz.4.2077/13641: #0: ffff888063412098 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:300 [inline] #0: ffff888063412098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock_pair_timeout drivers/tty/tty_ldisc.c:346 [inline] #0: ffff888063412098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock_pair drivers/tty/tty_ldisc.c:377 [inline] #0: ffff888063412098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_release+0x58/0x200 drivers/tty/tty_ldisc.c:802 #1: ffff888063416098 (&tty->ldisc_sem/1){+.+.}-{0:0}, at: __tty_ldisc_lock_nested drivers/tty/tty_ldisc.c:306 [inline] #1: ffff888063416098 (&tty->ldisc_sem/1){+.+.}-{0:0}, at: tty_ldisc_lock_pair_timeout drivers/tty/tty_ldisc.c:348 [inline] #1: ffff888063416098 (&tty->ldisc_sem/1){+.+.}-{0:0}, at: tty_ldisc_lock_pair drivers/tty/tty_ldisc.c:377 [inline] #1: ffff888063416098 (&tty->ldisc_sem/1){+.+.}-{0:0}, at: tty_ldisc_release+0x7c/0x200 drivers/tty/tty_ldisc.c:802 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe0f/0xe50 kernel/hung_task.c:369 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 144 Comm: kworker/u4:1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: netns cleanup_net RIP: 0010:preempt_count_add+0x2e/0x190 kernel/sched/core.c:5504 Code: 53 49 bf 00 00 00 00 00 fc ff df 48 c7 c0 80 7f 2d 96 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 eb 00 00 00 83 3d a2 1d db 14 00 <75> 07 65 8b 05 e1 0d b0 7e 65 01 3d da 0d b0 7e 48 c7 c0 80 7f 2d RSP: 0018:ffffc9000172eda8 EFLAGS: 00000246 RAX: 0000000000000004 RBX: ffffc9000172ee88 RCX: ffffffff962d7f03 RDX: dffffc0000000000 RSI: ffffffff87e1d1df RDI: 0000000000000001 RBP: ffffc9000172eed0 R08: ffffc9000172ef50 R09: 0000000000000008 R10: dffffc0000000000 R11: fffff520002e5ddd R12: ffffffff87e1d1df R13: ffffc9000172f7c0 R14: dffffc0000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3f6d5ec198 CR3: 00000000759de000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: unwind_next_frame+0xac/0x1d90 arch/x86/kernel/unwind_orc.c:433 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348 kvfree_call_rcu+0x105/0x7d0 kernel/rcu/tree.c:3600 __ipv6_dev_mc_dec+0x2bf/0x320 net/ipv6/mcast.c:981 addrconf_leave_solict net/ipv6/addrconf.c:2213 [inline] __ipv6_ifa_notify+0x75a/0xe60 net/ipv6/addrconf.c:6201 addrconf_ifdown+0xdff/0x19c0 net/ipv6/addrconf.c:3899 addrconf_notify+0x445/0xf00 net/ipv6/addrconf.c:-1 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391 call_netdevice_notifiers_extack net/core/dev.c:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] dev_close_many+0x29f/0x400 net/core/dev.c:1650 unregister_netdevice_many+0x481/0x19f0 net/core/dev.c:11110 default_device_exit_batch+0x364/0x3c0 net/core/dev.c:11667 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x791/0xba0 net/core/net_namespace.c:635 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287