INFO: task syz-executor:5640 blocked for more than 144 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22016 pid:5640 tgid:5640 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 bit_wait+0x11/0xd0 kernel/sched/wait_bit.c:240 __wait_on_bit+0xb9/0x310 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67 wait_on_bit include/linux/wait_bit.h:77 [inline] gfs2_glock_wait+0xbd/0x2a0 fs/gfs2/glock.c:1268 gfs2_glock_nq_init fs/gfs2/glock.h:253 [inline] __gfs2_lookup+0x134/0x2a0 fs/gfs2/inode.c:998 __lookup_slow+0x2b7/0x410 fs/namei.c:1915 lookup_slow+0x53/0x70 fs/namei.c:1932 walk_component fs/namei.c:2278 [inline] lookup_last fs/namei.c:2785 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2809 filename_lookup+0x256/0x5d0 fs/namei.c:2838 user_path_at+0x40/0x160 fs/namei.c:3643 ksys_umount fs/namespace.c:2062 [inline] __do_sys_umount fs/namespace.c:2070 [inline] __se_sys_umount fs/namespace.c:2068 [inline] __x64_sys_umount+0xf6/0x170 fs/namespace.c:2068 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: 0033:0x7f1c9859e097 RSP: 002b:00007ffce504fe88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 00007f1c986321ca RCX: 00007f1c9859e097 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffce504ff40 RBP: 00007ffce504ff40 R08: 0000000000000000 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffce5051030 R13: 00007f1c986321ca R14: 0000000000021bb1 R15: 00007ffce50531f0 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: #0: ffffffff8e962f28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #0: ffffffff8e962f28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961 1 lock held by khungtaskd/32: #0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5381: #0: ffff888036a970a0 (&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+0x45c/0x13a0 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/5613: 1 lock held by syz-executor/5640: #0: ffff88806b880e00 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1044 [inline] #0: ffff88806b880e00 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1931 6 locks held by kworker/u8:12/6333: #0: ffff88801bafe140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801bafe140 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc9000e38fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc9000e38fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8fdb9928 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673 #3: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline] #3: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x2a4/0x940 net/core/net_namespace.c:248 #4: ffff8880526a1590 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_netns_exit_rtnl+0xab/0x200 drivers/net/wireguard/device.c:423 #5: ffffffff8e962f28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #5: ffffffff8e962f28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961 3 locks held by kworker/u8:13/6335: #0: ffff88803201d140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88803201d140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc9000e3dfc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc9000e3dfc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4206 2 locks held by syz-executor/7503: #0: ffffffff8f544be8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8f544be8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8f544be8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4109 1 lock held by syz.5.422/7642: #0: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fdc8600 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3441 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP 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+0xfd3/0x1030 kernel/hung_task.c:561 kthread+0x389/0x470 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: 6333 Comm: kworker/u8:12 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: netns cleanup_net RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:408 Code: e2 80 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 3c 3b ec fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 12 6d cb fb cc 44 89 f9 80 e1 07 38 c1 RSP: 0018:ffffc9000e38f0d0 EFLAGS: 00000002 RAX: 0000000000000038 RBX: 0000000000000038 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020 RBP: 00000000000003f8 R08: ffff888140ad0237 R09: 1ffff1102815a046 R10: dffffc0000000000 R11: ffffffff8544d370 R12: dffffc0000000000 R13: ffffffff9a47a9a9 R14: ffffffff9a790ac0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812529c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f03cdbea2f8 CR3: 0000000058af5000 CR4: 0000000000350ef0 Call Trace: serial_port_out include/linux/serial_core.h:811 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3220 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline] serial8250_console_write+0x140c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3360 console_emit_next_record kernel/printk/printk.c:3183 [inline] console_flush_one_record kernel/printk/printk.c:3269 [inline] console_flush_all+0x718/0xb20 kernel/printk/printk.c:3343 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline] console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479 _printk+0xdd/0x130 kernel/printk/printk.c:2504 netdev_info+0x11e/0x180 net/core/dev.c:12996 __dev_set_promiscuity+0x2d4/0x6e0 net/core/dev.c:9618 netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9645 dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:288 nbp_delete_promisc net/bridge/br_if.c:254 [inline] del_nbp+0x12c/0xa60 net/bridge/br_if.c:340 br_dev_delete+0x6e/0x110 net/bridge/br_if.c:386 br_net_exit_rtnl+0xb1/0x120 net/bridge/br.c:414 ops_exit_rtnl_list net/core/net_namespace.c:181 [inline] ops_undo_list+0x347/0x940 net/core/net_namespace.c:248 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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