INFO: task syz-executor:6412 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:21336 pid:6412 tgid:6412 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x145f/0x5070 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241 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+0x2a8/0x6b0 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline] mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:552 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:643 kill_block_super+0x44/0x90 fs/super.c:1722 deactivate_locked_super+0xbc/0x130 fs/super.c:474 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318 task_work_run+0x1d4/0x260 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:44 [inline] exit_to_user_mode_loop+0xef/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2d3c450a77 RSP: 002b:00007ffc22639058 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f2d3c4d3d7d RCX: 00007f2d3c450a77 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc22639110 RBP: 00007ffc22639110 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc2263a1a0 R13: 00007f2d3c4d3d7d R14: 000000000002ec59 R15: 00007ffc2263a1e0 Showing all locks held in the system: 4 locks held by pr/legacy/17: 1 lock held by khungtaskd/38: #0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 6 locks held by kworker/u8:4/69: #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc9000154fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000154fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffffffff8e898800 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x7b0 net/core/net_namespace.c:670 #3: ffff8880393af0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #3: ffff8880393af0d8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline] #3: ffff8880393af0d8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0 net/devlink/core.c:506 #4: ffff8880393aa300 (&devlink->lock_key#17){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline] #4: ffff8880393aa300 (&devlink->lock_key#17){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline] #4: ffff8880393aa300 (&devlink->lock_key#17){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0 net/devlink/core.c:506 #5: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xed/0x680 drivers/net/netdevsim/netdev.c:1175 2 locks held by dhcpcd/5470: #0: ffff88804ce8c928 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xbd/0xe90 net/netlink/af_netlink.c:2267 #1: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6826 2 locks held by getty/5560: #0: ffff88814f1ab0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x44f/0x1460 drivers/tty/n_tty.c:2211 2 locks held by syz-executor/5804: #0: ffff88803c6820d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88803c6820d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88803c6820d0 (&type->s_umount_key#76){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8d9f9938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/6368: #0: ffff88802e4c60d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88802e4c60d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88802e4c60d0 (&type->s_umount_key#76){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8d9f9938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/6412: #0: ffff8880239560d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880239560d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880239560d0 (&type->s_umount_key#76){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8d9f9938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 5 locks held by kworker/u8:23/6633: 2 locks held by syz.7.148/6748: #0: ffff8880778780d0 (&type->s_umount_key#74/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344 #1: ffffffff8d9f9938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/6832: #0: ffff888038e160d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888038e160d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888038e160d0 (&type->s_umount_key#76){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8d9f9938 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 3 locks held by kworker/u8:28/7277: #0: ffff88813ff69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88813ff69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc90005227bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90005227bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 1 lock held by syz.4.204/7385: #0: ffff88803c6820d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88803c6820d0 (&type->s_umount_key#76){++++}-{4:4}, at: super_lock+0x25c/0x3b0 fs/super.c:121 1 lock held by syz-executor/7465: #0: ffff888027d040d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888027d040d0 (&type->s_umount_key#76){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888027d040d0 (&type->s_umount_key#76){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 4 locks held by syz-executor/7627: 2 locks held by syz-executor/8082: #0: ffffffff8edb5170 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8edb5170 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8edb5170 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071 2 locks held by syz-executor/8360: #0: ffffffff8edb4e28 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8edb4e28 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8edb4e28 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8e8a5938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071 ============================================= 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 10/25/2025 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:160 [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:346 [inline] watchdog+0xf95/0xfe0 kernel/hung_task.c:515 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:407 Code: d9 b5 fc 44 89 f9 d3 e5 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 dc 12 18 fd 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1 RSP: 0018:ffffc900001679b0 EFLAGS: 00000202 RAX: 0000000000000030 RBX: 0000000000000030 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000000003f8 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff8509d2f0 R12: dffffc0000000000 R13: 0000000000000001 R14: ffffffff98f9bd80 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126cee000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005640fff47138 CR3: 000000003d234000 CR4: 00000000003526f0 Call Trace: serial_port_out include/linux/serial_core.h:811 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline] serial8250_console_write+0x1291/0x1b40 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3109 [inline] console_flush_one_record+0x685/0xb80 kernel/printk/printk.c:3215 legacy_kthread_func+0x16f/0x210 kernel/printk/printk.c:3674 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246