INFO: task syz-executor.1:5035 blocked for more than 143 seconds. Not tainted 6.4.0-rc6-syzkaller-00037-gb6dad5178cea #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:19832 pid:5035 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: 0033:0x7f65a428d5b7 RSP: 002b:00007fff34f21f78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f65a428d5b7 RDX: 00007fff34f2204c RSI: 000000000000000a RDI: 00007fff34f22040 RBP: 00007fff34f22040 R08: 00000000ffffffff R09: 00007fff34f21e10 R10: 00005555568928e3 R11: 0000000000000246 R12: 00007f65a42e6c6b R13: 00007fff34f23100 R14: 0000555556892810 R15: 00007fff34f23140 Showing all locks held in the system: 4 locks held by kworker/u4:1/12: 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/u4:4/75: 2 locks held by getty/4758: #0: ffff88814ac39098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900015902f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ab/0x1db0 drivers/tty/n_tty.c:2176 2 locks held by syz-executor.1/5035: #0: ffff8880317ea0e0 (&type->s_umount_key#31){++++}-{3:3}, at: deactivate_super+0xad/0xf0 fs/super.c:361 #1: ffff8881413ea7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline] #1: ffff8881413ea7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x278/0xab0 fs/fs-writeback.c:2728 3 locks held by kworker/u4:10/1645: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.4.0-rc6-syzkaller-00037-gb6dad5178cea #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 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: 12 Comm: kworker/u4:1 Not tainted 6.4.0-rc6-syzkaller-00037-gb6dad5178cea #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Workqueue: writeback wb_workfn (flush-7:1) RIP: 0010:arch_clear_bit_unlock_is_negative_byte arch/x86/include/asm/bitops.h:101 [inline] RIP: 0010:clear_bit_unlock_is_negative_byte include/asm-generic/bitops/instrumented-lock.h:78 [inline] RIP: 0010:folio_unlock+0xe2/0x2f0 mm/filemap.c:1530 Code: 31 ff e8 f1 09 d0 ff 48 83 e5 01 0f 85 be 00 00 00 0f 1f 44 00 00 e8 9d 05 d0 ff 4c 89 f7 be 08 00 00 00 e8 00 df 27 00 31 db 41 80 26 fe 40 0f 98 c5 0f 98 c3 bf 02 00 00 00 89 de e8 06 08 RSP: 0018:ffffc90000116cc8 EFLAGS: 00000246 RAX: ffffffff81bb7a01 RBX: 0000000000000000 RCX: ffffffff81bb7a10 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffea00015140c0 RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff940002a2819 R10: 0000000000000000 R11: dffffc0000000001 R12: ffffea00015140c8 R13: 1ffffd40002a2819 R14: ffffea00015140c0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c000884000 CR3: 000000002bfde000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mpage_release_unused_pages+0x7dd/0x1070 fs/ext4/inode.c:1597 ext4_do_writepages+0x2c62/0x3da0 fs/ext4/inode.c:2721 ext4_writepages+0x203/0x3e0 fs/ext4/inode.c:2792 do_writepages+0x3a6/0x670 mm/page-writeback.c:2551 __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