INFO: task syz-executor:5693 blocked for more than 146 seconds. Not tainted 6.1.119-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20840 pid:5693 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 wb_wait_for_completion+0x162/0x290 fs/fs-writeback.c:191 sync_inodes_sb+0x28f/0xb10 fs/fs-writeback.c:2739 sync_filesystem+0x16b/0x220 fs/sync.c:64 generic_shutdown_super+0x6b/0x340 fs/super.c:474 kill_block_super+0x7a/0xe0 fs/super.c:1470 deactivate_locked_super+0xa0/0x110 fs/super.c:332 cleanup_mnt+0x490/0x520 fs/namespace.c:1186 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 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+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4c1f581247 RSP: 002b:00007ffc35605288 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f4c1f5f3824 RCX: 00007f4c1f581247 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc35605340 RBP: 00007ffc35605340 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc356063c0 R13: 00007f4c1f5f3824 R14: 000000000008cce2 R15: 00007ffc35606400 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8d32b110 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8d32b910 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/27: #0: ffffffff8d32af40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32af40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32af40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510 4 locks held by kworker/u4:4/75: 2 locks held by getty/4001: #0: ffff88814cae7098 (&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+0x6a7/0x1db0 drivers/tty/n_tty.c:2198 2 locks held by kworker/1:4/4292: #0: ffff888017c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc900043d7d20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 7 locks held by kworker/u4:14/4876: 2 locks held by syz-executor/5693: #0: ffff8880600080e0 (&type->s_umount_key#71){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 #1: ffff8881437e07d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff8881437e07d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 2 locks held by syz-executor/6759: #0: ffff88807d2380e0 (&type->s_umount_key#71){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 #1: ffff8881437647d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 1 lock held by dhcpcd/8914: #0: ffff88805e9c7410 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #0: ffff88805e9c7410 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline] #0: ffff88805e9c7410 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1400 1 lock held by dhcpcd/9689: #0: ffff888057a41410 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #0: ffff888057a41410 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline] #0: ffff888057a41410 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1400 1 lock held by syz-executor/9998: #0: ffffffff8d330538 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] ffffffff8d330538 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x930 kernel/rcu/tree_exp.h:962 4 locks held by kvm-nx-lpage-re/11303: #0: ffffffff8d353528 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline] #0: ffffffff8d353528 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_attach_task_all+0x23/0xe0 kernel/cgroup/cgroup-v1.c:61 #1: ffffffff8d1c82f0 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock+0xd/0x30 kernel/cgroup/cgroup.c:2453 #2: ffffffff8d353710 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_task_all+0x2d/0xe0 kernel/cgroup/cgroup-v1.c:62 #3: ffffffff8d330538 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #3: ffffffff8d330538 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x930 kernel/rcu/tree_exp.h:962 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted 6.1.119-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1ae/0x3f0 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+0xf88/0xfd0 kernel/hung_task.c:377 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4876 Comm: kworker/u4:14 Not tainted 6.1.119-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: writeback wb_workfn (flush-7:8) RIP: 0010:io_serial_in+0x72/0xb0 drivers/tty/serial/8250/8250_port.c:461 Code: f4 d1 cc fc 89 e9 41 d3 e6 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 f5 5a 24 fd 44 03 33 44 89 f2 ec <0f> b6 c0 5b 41 5e 41 5f 5d c3 89 e9 80 e1 07 38 c1 7c ad 48 89 ef RSP: 0018:ffffc90003bfddd8 EFLAGS: 00000002 RAX: 1ffffffff2edb500 RBX: ffffffff976da800 RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: 0000000000000000 R08: ffffffff84bdc9f2 R09: ffffed1004a00047 R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff97395e30 R13: 00000000000026e0 R14: 00000000000003fd R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8396e95440 CR3: 000000007e5ac000 CR4: 00000000003526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:117 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:139 [inline] wait_for_lsr drivers/tty/serial/8250/8250_port.c:2100 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3367 [inline] serial8250_console_write+0x1057/0x1750 drivers/tty/serial/8250/8250_port.c:3445 call_console_driver kernel/printk/printk.c:1977 [inline] console_emit_next_record+0xbb4/0x1000 kernel/printk/printk.c:2777 console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906 vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303 _printk+0xd1/0x111 kernel/printk/printk.c:2328 _udf_err+0x137/0x180 fs/udf/super.c:2353 udf_bitmap_new_block fs/udf/balloc.c:357 [inline] udf_new_block+0x1bb4/0x2130 fs/udf/balloc.c:730 inode_getblk fs/udf/inode.c:769 [inline] udf_get_block+0x1a69/0x5360 fs/udf/inode.c:359 __mpage_writepage+0x40d/0x1930 fs/mpage.c:533 write_cache_pages+0x92e/0x15c0 mm/page-writeback.c:2382 mpage_writepages+0x103/0x1d0 fs/mpage.c:664 do_writepages+0x3a2/0x670 mm/page-writeback.c:2491 __writeback_single_inode+0x15d/0x11e0 fs/fs-writeback.c:1612 writeback_sb_inodes+0xc2b/0x1b20 fs/fs-writeback.c:1903 wb_writeback+0x49d/0xe10 fs/fs-writeback.c:2077 wb_do_writeback fs/fs-writeback.c:2220 [inline] wb_workfn+0x427/0x1020 fs/fs-writeback.c:2260 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295