INFO: task syz-executor.1:5027 blocked for more than 143 seconds. Not tainted 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:20024 pid:5027 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5343 [inline] __schedule+0x187b/0x4900 kernel/sched/core.c:6669 schedule+0xc3/0x180 kernel/sched/core.c:6745 wb_wait_for_completion+0x166/0x290 fs/fs-writeback.c:192 sync_inodes_sb+0x297/0xab0 fs/fs-writeback.c:2730 sync_filesystem+0x16f/0x220 fs/sync.c:64 generic_shutdown_super+0x6f/0x340 fs/super.c:473 kill_block_super+0x84/0xf0 fs/super.c:1407 deactivate_locked_super+0xa4/0x110 fs/super.c:331 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1177 task_work_run+0x24a/0x300 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:297 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f613c08d5d7 RSP: 002b:00007ffdc90b6f28 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f613c08d5d7 RDX: 00007ffdc90b6ffa RSI: 000000000000000a RDI: 00007ffdc90b6ff0 RBP: 00007ffdc90b6ff0 R08: 00000000ffffffff R09: 00007ffdc90b6dc0 R10: 0000555557384893 R11: 0000000000000246 R12: 00007f613c0e6cdc R13: 00007ffdc90b80b0 R14: 0000555557384810 R15: 00007ffdc90b80f0 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/13: #0: ffffffff8cf276f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:518 1 lock held by rcu_tasks_trace/14: #0: ffffffff8cf27ab0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:518 2 locks held by kworker/u4:2/27: #0: ffff88801425f138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x77e/0x10e0 kernel/workqueue.c:2378 #1: ffffc90000a3fd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7c8/0x10e0 kernel/workqueue.c:2380 1 lock held by khungtaskd/29: #0: ffffffff8cf27520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by getty/4746: #0: ffff888028b62098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900015802f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ab/0x1db0 drivers/tty/n_tty.c:2176 2 locks held by syz-executor.1/5027: #0: ffff8880334e60e0 (&type->s_umount_key#69){+.+.}-{3:3}, at: deactivate_super+0xad/0xf0 fs/super.c:361 #1: ffff888140b027d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline] #1: ffff888140b027d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x278/0xab0 fs/fs-writeback.c:2728 2 locks held by segctord/7588: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x498/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x187/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xec2/0xf00 kernel/hung_task.c:379 kthread+0x2b8/0x350 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: kworker/u4:2 Not tainted 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: writeback wb_workfn (flush-7:1) RIP: 0010:lock_is_held_type+0xf0/0x190 Code: df 8c 48 89 de e8 20 aa bd f9 eb cb 31 ed eb 1f 41 83 fe ff 74 14 31 c0 f6 45 22 03 0f 95 c0 31 ed 44 39 f0 40 0f 94 c5 eb 05 01 00 00 00 48 c7 c7 a0 9f ea 8a e8 af 16 00 00 b8 ff ff ff ff RSP: 0018:ffffc90000a3ec90 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000002 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: ffff8880b993c1d8 RDI: ffff888018a64698 RBP: ffff888018a64698 R08: dffffc0000000000 R09: fffffbfff206504d R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000046 R13: ffff888018a63b80 R14: 00000000ffffffff R15: ffff8880b993c1d8 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c0006d0000 CR3: 000000002a187000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held include/linux/lockdep.h:288 [inline] lockdep_assert_rq_held kernel/sched/sched.h:1357 [inline] do_balance_callbacks kernel/sched/core.c:4976 [inline] __balance_callbacks+0xb4/0x270 kernel/sched/core.c:5038 finish_lock_switch+0x84/0x110 kernel/sched/core.c:5094 finish_task_switch+0x134/0x650 kernel/sched/core.c:5213 context_switch kernel/sched/core.c:5346 [inline] __schedule+0x1883/0x4900 kernel/sched/core.c:6669 schedule+0xc3/0x180 kernel/sched/core.c:6745 nilfs_segctor_sync+0x3d7/0x5e0 fs/nilfs2/segment.c:2216 writepage_cb+0x64/0x130 mm/page-writeback.c:2535 write_cache_pages+0x89e/0x12b0 mm/page-writeback.c:2473 do_writepages+0x412/0x670 mm/page-writeback.c:2556 __writeback_single_inode+0x155/0xfa0 fs/fs-writeback.c:1603 writeback_sb_inodes+0x8e3/0x11d0 fs/fs-writeback.c:1894 wb_writeback+0x458/0xc70 fs/fs-writeback.c:2068 wb_do_writeback fs/fs-writeback.c:2211 [inline] wb_workfn+0x400/0xff0 fs/fs-writeback.c:2251 process_one_work+0x8a0/0x10e0 kernel/workqueue.c:2405 worker_thread+0xa63/0x1210 kernel/workqueue.c:2552 kthread+0x2b8/0x350 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308