INFO: task syz-executor.2:5031 blocked for more than 143 seconds. Not tainted 6.4.0-syzkaller-10173-ga901a3568fd2 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.2 state:D stack:20456 pid:5031 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1873/0x48f0 kernel/sched/core.c:6710 schedule+0xc3/0x180 kernel/sched/core.c:6786 wb_wait_for_completion+0x166/0x290 fs/fs-writeback.c:192 sync_inodes_sb+0x297/0xab0 fs/fs-writeback.c:2736 sync_filesystem+0x16f/0x220 fs/sync.c:64 generic_shutdown_super+0x6f/0x340 fs/super.c:472 kill_block_super+0x68/0xa0 fs/super.c:1417 deactivate_locked_super+0xa4/0x110 fs/super.c:330 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1254 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: 0033:0x7fa6dd08d7f7 RSP: 002b:00007ffdc8d62308 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fa6dd08d7f7 RDX: 00007ffdc8d623db RSI: 000000000000000a RDI: 00007ffdc8d623d0 RBP: 00007ffdc8d623d0 R08: 00000000ffffffff R09: 00007ffdc8d621a0 R10: 00005555559e88e3 R11: 0000000000000246 R12: 00007fa6dd0d643b R13: 00007ffdc8d63490 R14: 00005555559e8810 R15: 00007ffdc8d634d0 Showing all locks held in the system: 2 locks held by kworker/u4:1/12: 1 lock held by rcu_tasks_kthre/13: #0: ffffffff8d326af0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:522 1 lock held by rcu_tasks_trace/14: #0: ffffffff8d326eb0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:522 1 lock held by khungtaskd/28: #0: ffffffff8d326920 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 8 locks held by kworker/u4:6/2796: 2 locks held by getty/4753: #0: ffff88802d822098 (&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+0x6b1/0x1db0 drivers/tty/n_tty.c:2176 2 locks held by syz-executor.2/5031: #0: ffff8880197960e0 ( &type->s_umount_key #31){++++}-{3:3}, at: deactivate_super+0xad/0xf0 fs/super.c:360 #1: ffff88814171e7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline] #1: ffff88814171e7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x278/0xab0 fs/fs-writeback.c:2734 2 locks held by kworker/u4:8/9056: #0: ffff8880b993bf98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558 #1: ffffc90014f57d20 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}, at: process_one_work+0x82b/0x12c0 kernel/workqueue.c:2571 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.4.0-syzkaller-10173-ga901a3568fd2 #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:160 [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:389 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 20102 Comm: kworker/u4:9 Not tainted 6.4.0-syzkaller-10173-ga901a3568fd2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Workqueue: bat_events batadv_dat_purge