INFO: task syz-executor:4260 blocked for more than 143 seconds. Not tainted 6.1.135-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22240 pid:4260 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 wb_wait_for_completion+0x162/0x280 fs/fs-writeback.c:191 sync_inodes_sb+0x1b8/0x9e0 fs/fs-writeback.c:2739 sync_filesystem+0x16d/0x220 fs/sync.c:64 generic_shutdown_super+0x6b/0x340 fs/super.c:474 kill_block_super+0x7c/0xe0 fs/super.c:1470 deactivate_locked_super+0x93/0xf0 fs/super.c:332 cleanup_mnt+0x463/0x4f0 fs/namespace.c:1186 task_work_run+0x1ca/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f856d98fc97 RSP: 002b:00007ffed8c2fe78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f856da1089d RCX: 00007f856d98fc97 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffed8c2ff30 RBP: 00007ffed8c2ff30 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffed8c30fc0 R13: 00007f856da1089d R14: 000000000008c7c2 R15: 00007ffed8c31000 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8c92b370 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8c92bb90 ( rcu_tasks_trace.tasks_gp_mutex ){+.+.}-{3:3} , at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 3 locks held by kworker/1:1/26: #0: ffff88814d387d38 ( (wq_completion)ipv6_addrconf ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90000a1fd00 ( (work_completion)(&(&ifa->dad_work)->work) ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffffffff8db33868 ( rtnl_mutex ){+.+.}-{3:3} , at: addrconf_dad_work+0xc4/0x14d0 net/ipv6/addrconf.c:4134 1 lock held by khungtaskd/28: #0: ffffffff8c92a9e0 ( rcu_read_lock ){....}-{1:2} , at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] , at: rcu_read_lock include/linux/rcupdate.h:791 [inline] , at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 5 locks held by kworker/u4:2/33: 3 locks held by kworker/u4:3/51: #0: ffff888017479138 ( (wq_completion)events_unbound ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90000bc7d00 ( (linkwatch_work).work ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263 3 locks held by kworker/0:2/125: #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90002d87d00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:104 4 locks held by udevd/3622: #0: ffff8880649c30a0 ( &p->lock ){+.+.}-{3:3} , at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182 #1: ffff888059682c88 ( &of->mutex ){+.+.}-{3:3}, at: kernfs_seq_start+0x51/0x3b0 fs/kernfs/file.c:154 #2: ffff888064386bd0 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x3b0 fs/kernfs/file.c:155 #3: ffff888055c020e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #3: ffff888055c020e8 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2669 2 locks held by dhcpcd/3915: #0: ffffffff8db19a08 (vlan_ioctl_mutex){+.+.}-{3:3}, at: sock_ioctl+0x273/0x6e0 net/socket.c:1283 #1: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: vlan_ioctl_handler+0xd2/0x5f0 net/8021q/vlan.c:554 2 locks held by getty/4008: #0: ffff88802fa3f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198 2 locks held by syz-executor/4260: #0: ffff88801ebea0e0 (&type->s_umount_key#97){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362 #1: ffff888143b6e7d0 ( &bdi->wb_switch_rwsem ){+.+.}-{3:3} , at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] , at: sync_inodes_sb+0x19c/0x9e0 fs/fs-writeback.c:2737 2 locks held by kworker/1:7/4302: #0: ffff888017472138 ( (wq_completion)rcu_gp ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90004187d00 ( (work_completion)(&rew->rew_work) ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 2 locks held by kworker/u4:7/4340: #0: ffff888143ab2138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90004577d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 3 locks held by kworker/u4:9/4363: 5 locks held by kworker/u4:12/4456: #0: ffff888017616938 ((wq_completion)netns ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc900048bfd00 ( net_cleanup_work ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffffffff8db26c10 ( pernet_ops_rwsem ){++++}-{3:3} , at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:594 #3: ffffffff8db33868 ( rtnl_mutex ){+.+.}-{3:3} , at: default_device_exit_batch+0xe5/0xa50 net/core/dev.c:11477 #4: ffffffff8c9306b8 ( rcu_state.exp_mutex ){+.+.}-{3:3} , at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] , at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962 3 locks held by kworker/0:8/5433: #0: ffff88814d387d38 ( (wq_completion)ipv6_addrconf ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90003227d00 ( (work_completion)(&(&ifa->dad_work)->work) ){+.+.}-{0:0} , at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffffffff8db33868 ( rtnl_mutex ){+.+.}-{3:3} , at: addrconf_dad_work+0xc4/0x14d0 net/ipv6/addrconf.c:4134 4 locks held by segctord/11107: 1 lock held by syz.2.1437/11340: #0: ffff88801ebea0e0 ( &type->s_umount_key #97 ){++++}-{3:3} , at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz-executor/11502: #0: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6150 1 lock held by syz-executor/11504: #0: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6150 4 locks held by syz-executor/11619: #0: ffff88807f14e460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580 #1: ffff88805727fc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:325 #2: ffff8880268c5a00 (kn->active#51){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:326 #3: ffffffff8d44d508 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: new_device_store+0x129/0x670 drivers/net/netdevsim/bus.c:160 7 locks held by syz-executor/11633: #0: ffff88807f14e460 (sb_writers#8){.+.+}-{0:0} , at: vfs_write+0x256/0x960 fs/read_write.c:580 #1: ffff88805722a488 (&of->mutex ){+.+.}-{3:3} , at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:325 #2: ffff8880268c5a00 ( kn->active #51 ){.+.+}-{0:0} , at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:326 #3: ffffffff8d44d508 ( nsim_bus_dev_list_lock ){+.+.}-{3:3} , at: new_device_store+0x129/0x670 drivers/net/netdevsim/bus.c:160 #4: ffff888055c020e8 ( &dev->mutex ){....}-{3:3} , at: device_lock include/linux/device.h:837 [inline] , at: __device_attach+0x85/0x460 drivers/base/dd.c:990 #5: ffff888028ede2f8 ( &devlink->lock_key #12 ){+.+.}-{3:3} , at: nsim_drv_probe+0xc0/0xaf0 drivers/net/netdevsim/dev.c:1542 #6: ffffffff8db33868 ( rtnl_mutex ){+.+.}-{3:3} , at: register_nexthop_notifier+0x7d/0x210 net/ipv4/nexthop.c:3606 1 lock held by syz-executor/11710: #0: ffffffff8db33868 ( rtnl_mutex ){+.+.}-{3:3} , at: rtnl_lock net/core/rtnetlink.c:74 [inline] , at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6150 1 lock held by syz-executor/11746: #0: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6150 1 lock held by syz-executor/11749: #0: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8db33868 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6150 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.135-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 11107 Comm: segctord Not tainted 6.1.135-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:io_serial_in+0x73/0xb0 drivers/tty/serial/8250/8250_port.c:461 Code: e8 32 34 09 fd 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 43 a2 5a fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 44 89 f9 80 e1 07 38 c1 7c aa 4c RSP: 0018:ffffc90003686d58 EFLAGS: 00000006 RAX: 1ffffffff2da8b05 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffc90003686f50 R08: 0000000000000004 R09: 0000000000000003 R10: fffff520006d0d8c R11: 1ffff920006d0d8c R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff96d45820 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5f7a2e5000 CR3: 000000007f6ac000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_port_in include/linux/serial_core.h:668 [inline] serial8250_console_write+0x247/0x17a0 drivers/tty/serial/8250/8250_port.c:3438 call_console_driver kernel/printk/printk.c:1977 [inline] console_emit_next_record+0x947/0xc90 kernel/printk/printk.c:2777 console_flush_all kernel/printk/printk.c:-1 [inline] console_unlock+0x223/0x630 kernel/printk/printk.c:2906 vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303 _printk+0xcc/0x110 kernel/printk/printk.c:2328 show_trace_log_lvl+0x4d0/0x550 arch/x86/kernel/dumpstack.c:284 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 __getblk_slow fs/buffer.c:1026 [inline] __getblk_gfp+0x1c3/0xb20 fs/buffer.c:1333 sb_getblk include/linux/buffer_head.h:356 [inline] nilfs_segbuf_extend_segsum+0xcb/0x360 fs/nilfs2/segbuf.c:99 nilfs_segbuf_reset+0x33/0x140 fs/nilfs2/segbuf.c:135 nilfs_segctor_reset_segment_buffer fs/nilfs2/segment.c:421 [inline] nilfs_segctor_collect fs/nilfs2/segment.c:1530 [inline] nilfs_segctor_do_construct+0x12e4/0x6810 fs/nilfs2/segment.c:2090 nilfs_segctor_construct+0x17b/0x690 fs/nilfs2/segment.c:2453 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2561 [inline] nilfs_segctor_thread+0x4f2/0xff0 fs/nilfs2/segment.c:2645 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295