INFO: task syz-executor203:4996 blocked for more than 143 seconds. Not tainted 6.4.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor203 state:D stack:24808 pid:4996 ppid:4993 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5343 [inline] __schedule+0xc9a/0x5880 kernel/sched/core.c:6669 schedule+0xde/0x1a0 kernel/sched/core.c:6745 wb_wait_for_completion+0x182/0x240 fs/fs-writeback.c:192 sync_inodes_sb+0x1aa/0xa60 fs/fs-writeback.c:2730 sync_filesystem.part.0+0xe6/0x1d0 fs/sync.c:64 sync_filesystem+0x8f/0xc0 fs/sync.c:43 generic_shutdown_super+0x74/0x480 fs/super.c:473 kill_block_super+0xa1/0x100 fs/super.c:1407 deactivate_locked_super+0x98/0x160 fs/super.c:331 deactivate_super+0xb1/0xd0 fs/super.c:362 cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1177 task_work_run+0x16f/0x270 kernel/task_work.c:179 ptrace_notify+0x118/0x140 kernel/signal.c:2369 ptrace_report_syscall include/linux/ptrace.h:411 [inline] ptrace_report_syscall_exit include/linux/ptrace.h:473 [inline] syscall_exit_work kernel/entry/common.c:252 [inline] syscall_exit_to_user_mode_prepare+0x129/0x220 kernel/entry/common.c:279 __syscall_exit_to_user_mode_work kernel/entry/common.c:284 [inline] syscall_exit_to_user_mode+0xd/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f7b49a94c97 RSP: 002b:00007ffd7de03a98 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f7b49a94c97 RDX: 00007ffd7de03b59 RSI: 000000000000000a RDI: 00007ffd7de03b50 RBP: 00007ffd7de03b50 R08: 00000000ffffffff R09: 00007ffd7de03930 R10: 0000555556dbd653 R11: 0000000000000202 R12: 00007ffd7de04bb0 R13: 0000555556dbd5f0 R14: 00007ffd7de03ac0 R15: 0000000000000001 Showing all locks held in the system: 2 locks held by kworker/u4:1/12: #0: ffff88801967e938 ((wq_completion)writeback){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88801967e938 ((wq_completion)writeback){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff88801967e938 ((wq_completion)writeback){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1324 [inline] #0: ffff88801967e938 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:643 [inline] #0: ffff88801967e938 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:670 [inline] #0: ffff88801967e938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x883/0x15e0 kernel/workqueue.c:2376 #1: ffffc90000117db0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x15e0 kernel/workqueue.c:2380 1 lock held by rcu_tasks_kthre/13: #0: ffffffff8c798430 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:518 1 lock held by rcu_tasks_trace/14: #0: ffffffff8c798130 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:518 1 lock held by khungtaskd/28: #0: ffffffff8c799040 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6545 2 locks held by getty/4748: #0: ffff888027dc3098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x26/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900015a02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef4/0x13e0 drivers/tty/n_tty.c:2176 2 locks held by syz-executor203/4996: #0: ffff88802b31a0e0 (&type->s_umount_key#42){+.+.}-{3:3}, at: deactivate_super+0xa9/0xd0 fs/super.c:361 #1: ffff88801ee6c7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline] #1: ffff88801ee6c7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x190/0xa60 fs/fs-writeback.c:2728 3 locks held by segctord/4999: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.4.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 nmi_cpu_backtrace+0x29c/0x350 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x2a4/0x300 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+0xe16/0x1090 kernel/hung_task.c:379 kthread+0x344/0x440 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: 12 Comm: kworker/u4:1 Not tainted 6.4.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4771 [inline] RIP: 0010:__lock_acquire+0x711/0x5df0 kernel/locking/lockdep.c:5024 Code: 20 66 81 e2 ff 1f 0f b7 da be 08 00 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 00 8d 52 91 e8 67 8e 71 00 48 0f a3 1d bf 0a ed 0f <0f> 82 3f ff ff ff 48 c7 c0 00 74 df 91 48 c1 e8 03 42 0f b6 14 38 RSP: 0018:ffffc90000117280 EFLAGS: 00000047 RAX: 0000000000000001 RBX: 00000000000005b0 RCX: ffffffff81658239 RDX: fffffbfff22a51b7 RSI: 0000000000000008 RDI: ffffffff91528db0 RBP: 0000000000000004 R08: 0000000000000000 R09: ffffffff91528db7 R10: fffffbfff22a51b6 R11: 0000000000000000 R12: 0000000000000000 R13: ffff888014a65940 R14: ffff888014a66408 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055b7a9ec0690 CR3: 000000000c571000 CR4: 0000000000350ee0 Call Trace: lock_acquire kernel/locking/lockdep.c:5691 [inline] lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5656 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 __folio_mark_dirty+0x2b/0xdf0 mm/page-writeback.c:2664 filemap_dirty_folio+0xa0/0x130 mm/page-writeback.c:2701 folio_redirty_for_writepage+0xdc/0x120 mm/page-writeback.c:2762 nilfs_mdt_write_page+0xd3/0x280 fs/nilfs2/mdt.c:420 writepage_cb+0x64/0x180 mm/page-writeback.c:2535 write_cache_pages+0x4a2/0xd30 mm/page-writeback.c:2473 do_writepages+0x2b1/0x640 mm/page-writeback.c:2556 __writeback_single_inode+0x121/0xdb0 fs/fs-writeback.c:1603 writeback_sb_inodes+0x54d/0xe70 fs/fs-writeback.c:1894 wb_writeback+0x294/0xa50 fs/fs-writeback.c:2068 wb_do_writeback fs/fs-writeback.c:2211 [inline] wb_workfn+0x2a5/0xfc0 fs/fs-writeback.c:2251 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552 kthread+0x344/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.098 msecs