INFO: task syz-executor:7334 blocked for more than 143 seconds. Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:17576 pid:7334 tgid:7334 ppid:1 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 wb_wait_for_completion+0x15f/0x260 fs/fs-writeback.c:216 __writeback_inodes_sb_nr+0x1f6/0x250 fs/fs-writeback.c:2747 sync_filesystem+0xa3/0x230 fs/sync.c:54 generic_shutdown_super+0x6f/0x2c0 fs/super.c:621 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2620 deactivate_locked_super+0xb9/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1431 task_work_run+0x1d1/0x260 kernel/task_work.c:227 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50 exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff496b8fc97 RSP: 002b:00007ffce3b50328 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007ff496c1089d RCX: 00007ff496b8fc97 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffce3b503e0 RBP: 00007ffce3b503e0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffce3b51470 R13: 00007ff496c1089d R14: 000000000006d1ac R15: 00007ffce3b514b0 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: #0: ffffffff8df43338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df43338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 1 lock held by khungtaskd/31: #0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 2 locks held by kworker/u8:4/63: 2 locks held by kworker/u8:7/3532: #0: ffff888143eab148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888143eab148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc9000bb27c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000bb27c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 2 locks held by getty/5577: #0: ffff8880304450a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/7334: #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 2 locks held by syz-executor/10047: 1 lock held by syz.2.771/12848: #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.2.771/12880: #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.6.777/12944: #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.6.777/12945: #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz-executor/13267: #0: ffffffff8df43338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df43338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 1 lock held by syz.3.974/14911: #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805c09a0e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 2 locks held by syz.4.973/14914: 2 locks held by sed/14924: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 3 Comm: pool_workqueue_ Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:remove_class_from_lock_chain kernel/locking/lockdep.c:6195 [inline] RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:6234 [inline] RIP: 0010:zap_class+0xc2/0x360 kernel/locking/lockdep.c:6279 Code: 49 81 fc 00 00 08 00 0f 84 a5 01 00 00 4e 8b 2c e5 10 e7 35 93 4d 85 ed 0f 94 c0 49 83 c5 f8 0f 94 c1 08 c1 75 d7 45 8b 7d 00 <41> f6 c7 fc 0f 84 e2 00 00 00 41 c1 ef 08 4e 8d 34 7d e0 e6 7a 92 RSP: 0018:ffffc90000087c60 EFLAGS: 00000046 RAX: 000000000007f400 RBX: 0000000000000db4 RCX: 000000000007f400 RDX: ffffffff9377e738 RSI: ffffffff9377e738 RDI: ffffffff93259b90 RBP: ffffffff9379eb80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff81ab0928 R12: 0000000000031b71 R13: ffffffff9399f6c0 R14: ffffffff928ad034 R15: 0000000004d7e40c FS: 0000000000000000(0000) GS:ffff8881260fb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe6835f538 CR3: 00000000592a6000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lockdep_free_key_range kernel/locking/lockdep.c:6405 [inline] lockdep_unregister_key+0x1a6/0x310 kernel/locking/lockdep.c:6607 wq_unregister_lockdep kernel/workqueue.c:4816 [inline] pwq_release_workfn+0x6d5/0x870 kernel/workqueue.c:5112 kthread_worker_fn+0x504/0xb60 kernel/kthread.c:1010 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245