INFO: task syz-executor.3:5026 blocked for more than 143 seconds. Not tainted 6.4.0-rc4-syzkaller-00268-g51f269a6ecc7 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.3 state:D stack:19472 pid:5026 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: 0033:0x7fc98308d5d7 RSP: 002b:00007fffac87ac98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fc98308d5d7 RDX: 00007fffac87ad6b RSI: 000000000000000a RDI: 00007fffac87ad60 RBP: 00007fffac87ad60 R08: 00000000ffffffff R09: 00007fffac87ab30 R10: 0000555556133893 R11: 0000000000000246 R12: 00007fc9830e6cdc R13: 00007fffac87be20 R14: 0000555556133810 R15: 00007fffac87be60 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 1 lock held by khungtaskd/28: #0: ffffffff8cf27520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by kworker/u4:2/41: 2 locks held by getty/4753: #0: ffff88814af15098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900015b02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ab/0x1db0 drivers/tty/n_tty.c:2176 2 locks held by syz-executor.3/5026: #0: ffff8880379860e0 (&type->s_umount_key#86){+.+.}-{3:3}, at: deactivate_super+0xad/0xf0 fs/super.c:361 #1: ffff88801eb7a7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline] #1: ffff88801eb7a7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x278/0xab0 fs/fs-writeback.c:2728 2 locks held by kworker/u4:7/5981: #0: ffff888012a9d938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x77e/0x10e0 kernel/workqueue.c:2378 #1: ffffc90015357d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7c8/0x10e0 kernel/workqueue.c:2380 2 locks held by segctord/11646: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.4.0-rc4-syzkaller-00268-g51f269a6ecc7 #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: 5981 Comm: kworker/u4:7 Not tainted 6.4.0-rc4-syzkaller-00268-g51f269a6ecc7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: writeback wb_workfn (flush-7:3) RIP: 0010:mapping_can_writeback include/linux/backing-dev.h:150 [inline] RIP: 0010:folio_account_redirty+0x94/0x640 mm/page-writeback.c:2728 Code: d5 08 00 48 89 c5 48 83 c5 44 48 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 0f 85 29 04 00 00 8b 6d 00 <89> ee 83 e6 01 31 ff e8 d0 de cc ff 40 f6 c5 01 75 1b e8 15 db cc RSP: 0018:ffffc90015357090 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888074abd6c8 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888074abd4a0 RBP: 0000000000000003 R08: ffffffff81ffa84d R09: fffffbfff1cab98e R10: 0000000000000000 R11: dffffc0000000001 R12: ffffea00009ddd80 R13: ffffea00009ddd80 R14: 1ffff1100e957ad9 R15: 00fff00000002033 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005597996cc680 CR3: 000000000cd30000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: folio_redirty_for_writepage+0x117/0x220 mm/page-writeback.c:2763 nilfs_mdt_write_page+0xc8/0x230 fs/nilfs2/mdt.c:420 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