INFO: task syz-executor:22452 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:21368 pid:22452 tgid:22452 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6864 __schedule_loop kernel/sched/core.c:6946 [inline] schedule+0x165/0x360 kernel/sched/core.c:6961 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7018 __mutex_lock_common kernel/locking/mutex.c:686 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:770 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:1328 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+0xff/0x4f0 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+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb783d90a77 RSP: 002b:00007ffd7ee68e38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fb783e13d7d RCX: 00007fb783d90a77 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd7ee68ef0 RBP: 00007ffd7ee68ef0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd7ee69f80 R13: 00007fb783e13d7d R14: 00000000000f19ae R15: 00007ffd7ee69fc0 INFO: task syz.6.3954:23413 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.3954 state:D stack:25336 pid:23413 tgid:23412 ppid:22679 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6864 __schedule_loop kernel/sched/core.c:6946 [inline] schedule+0x165/0x360 kernel/sched/core.c:6961 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7018 __mutex_lock_common kernel/locking/mutex.c:686 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:770 open_dummy_log fs/jfs/jfs_logmgr.c:1191 [inline] lmLogOpen+0x1a1/0xfa0 fs/jfs/jfs_logmgr.c:1066 jfs_mount_rw+0xe9/0x670 fs/jfs/jfs_mount.c:257 jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 vfs_get_tree+0x92/0x2a0 fs/super.c:1751 fc_mount fs/namespace.c:1209 [inline] do_new_mount_fc fs/namespace.c:3646 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3722 do_mount fs/namespace.c:4045 [inline] __do_sys_mount fs/namespace.c:4234 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4211 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7faa1db90eea RSP: 002b:00007faa1e9cfe68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007faa1e9cfef0 RCX: 00007faa1db90eea RDX: 0000200000000100 RSI: 00002000000000c0 RDI: 00007faa1e9cfeb0 RBP: 0000200000000100 R08: 00007faa1e9cfef0 R09: 0000000001010006 R10: 0000000001010006 R11: 0000000000000246 R12: 00002000000000c0 R13: 00007faa1e9cfeb0 R14: 00000000000061b6 R15: 0000200000001180 Showing all locks held in the system: 1 lock held by rcu_exp_gp_kthr/18: 1 lock held by khungtaskd/31: #0: ffffffff8df419e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df419e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df419e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5580: #0: ffff88814d8550a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211 3 locks held by kworker/0:7/5968: #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3236 #1: ffffc900048efb80 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3237 #2: ffff88805478a240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1f7/0x3b0 drivers/net/netdevsim/fib.c:1490 1 lock held by syz.7.3618/21235: #0: ffff8880467340e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff8880467340e0 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 2 locks held by syz-executor/21786: #0: ffff8880467340e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880467340e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880467340e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8e38e3a8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/22452: #0: ffff88802d5f00e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88802d5f00e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88802d5f00e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8e38e3a8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/22905: #0: ffff88806335e0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88806335e0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88806335e0e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8e38e3a8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz.6.3954/23413: #0: ffff88806a6120e0 (&type->s_umount_key#70/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xaa0 fs/super.c:344 #1: ffffffff8e38e3a8 (jfs_log_mutex){+.+.}-{4:4}, at: open_dummy_log fs/jfs/jfs_logmgr.c:1191 [inline] #1: ffffffff8e38e3a8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogOpen+0x1a1/0xfa0 fs/jfs/jfs_logmgr.c:1066 2 locks held by syz-executor/23582: #0: ffff88807cfc60e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88807cfc60e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88807cfc60e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8e38e3a8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/24049: #0: ffff88807a9240e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88807a9240e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88807a9240e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8e38e3a8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 2 locks held by syz-executor/24701: #0: ffff888057e260e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888057e260e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888057e260e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffffffff8e38e3a8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443 1 lock held by syz.9.4331/24925: #0: ffff8880467340e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff8880467340e0 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz-executor/24977: #0: ffffffff8df47538 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #0: ffffffff8df47538 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:956 1 lock held by syz-executor/25084: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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] __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+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 25084 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:preempt_count_sub+0x4c/0x170 kernel/sched/core.c:5757 Code: 85 c5 00 00 00 83 3d 82 44 f7 17 00 75 25 65 8b 05 89 00 ec 10 89 c1 81 e1 ff ff ff 7f 39 cf 7f 2a 81 ff ff 00 00 00 0f 93 c1 <84> c0 0f 95 c0 08 c8 74 58 65 8b 05 64 00 ec 10 f7 df 65 01 3d 5b RSP: 0018:ffffc9000540e518 EFLAGS: 00000093 RAX: 0000000000000003 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 0000000000000251 RSI: ffffffff8bc018c0 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffff888024fb0237 R09: 1ffff110049f6046 R10: dffffc0000000000 R11: ffffffff8b5805f0 R12: 1ffffffff337b482 R13: 00000000ffffffff R14: 0000025192b14364 R15: 00000000000006d8 FS: 0000555585e52500(0000) GS:ffff888125f4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc3fc1ff78 CR3: 0000000049dd4000 CR4: 00000000003526f0 Call Trace: delay_tsc+0x4e/0xc0 arch/x86/lib/delay.c:77 udelay include/asm-generic/delay.h:62 [inline] wait_for_lsr+0x160/0x2f0 drivers/tty/serial/8250/8250_port.c:1967 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline] serial8250_console_write+0x134c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3129 [inline] console_flush_one_record kernel/printk/printk.c:3215 [inline] console_flush_all+0x745/0xb60 kernel/printk/printk.c:3289 __console_flush_and_unlock kernel/printk/printk.c:3319 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3359 vprintk_emit+0x4f8/0x5f0 kernel/printk/printk.c:2426 _printk+0xcf/0x120 kernel/printk/printk.c:2451 batadv_hardif_activate_interface+0x17e/0x2a0 net/batman-adv/hard-interface.c:670 batadv_hard_if_event+0x34f/0x1240 net/batman-adv/hard-interface.c:965 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2269 [inline] call_netdevice_notifiers net/core/dev.c:2283 [inline] __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9803 do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3158 rtnl_changelink net/core/rtnetlink.c:3776 [inline] __rtnl_newlink net/core/rtnetlink.c:3935 [inline] rtnl_newlink+0x161c/0x1c90 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:728 __sock_sendmsg net/socket.c:743 [inline] __sys_sendto+0x3ce/0x540 net/socket.c:2212 __do_sys_sendto net/socket.c:2219 [inline] __se_sys_sendto net/socket.c:2215 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2215 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff8c8b915dc Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b RSP: 002b:00007ffdadcff3f0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007ff8c9914620 RCX: 00007ff8c8b915dc RDX: 000000000000002c RSI: 00007ff8c9914670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffdadcff444 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007ff8c9914670 R15: 0000000000000000