INFO: task syz-executor:5826 blocked for more than 143 seconds. Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22008 pid:5826 tgid:5826 ppid:1 task_flags:0x400140 flags:0x00004006 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: 0033:0x7f062a98fc97 RSP: 002b:00007ffc93a57858 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f062aa1089d RCX: 00007f062a98fc97 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc93a57910 RBP: 00007ffc93a57910 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc93a589a0 R13: 00007f062aa1089d R14: 000000000001be85 R15: 00007ffc93a589e0 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 2 locks held by kworker/u8:3/53: #0: ffff888020ae0948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888020ae0948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90000be7c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90000be7c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 2 locks held by getty/5580: #0: ffff88803445a0a0 (&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/5826: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 3 locks held by kworker/u8:8/6515: #0: ffff8880b88399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 #1: ffff8880b8823b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987 #2: ffff8880b8825558 (&base->lock){-.-.}-{2:2}, at: lock_timer_base kernel/time/timer.c:1046 [inline] #2: ffff8880b8825558 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30 kernel/time/timer.c:1127 1 lock held by syz.3.105/6586: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.3.105/6588: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.3.105/6590: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.3.105/6594: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.3.105/6597: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.3.105/6599: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.3.105/6601: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.3.105/6605: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by dhcpcd/7533: #0: ffff88807c77b808 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #0: ffff88807c77b808 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline] #0: ffff88807c77b808 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1391 1 lock held by syz.5.229/7638: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.5.229/7659: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz-executor/7860: #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998 1 lock held by syz.4.225/8009: #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805cd240e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.9.292/8228: #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 2 locks held by dhcpcd-run-hook/8239: #0: ffff8880b88399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 #1: ffff8880b8823b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987 1 lock held by dhcpcd-run-hook/8244: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #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: 6520 Comm: kworker/u8:13 Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:trace_hardirqs_off+0x2f/0x40 kernel/trace/trace_preemptirq.c:109 Code: 48 8b 5c 24 08 48 89 df e8 1e bb 87 09 65 8b 05 f7 b7 ab 10 85 c0 74 07 5b c3 cc cc cc cc cc 65 c7 05 e1 b7 ab 10 01 00 00 00 <48> 89 df 5b e9 a8 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 RSP: 0018:ffffc90004e77970 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffffffff8185c59e RCX: 2d0fff61cb638100 RDX: 0000000000000000 RSI: ffffffff8d7377ae RDI: ffffffff8bc0ffa0 RBP: ffffc90004e77a18 R08: ffff88805ccd9003 R09: 1ffff1100b99b200 R10: dffffc0000000000 R11: ffffed100b99b201 R12: ffffffff8b1d7078 R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff920009cef30 FS: 0000000000000000(0000) GS:ffff888126100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055e141b58660 CR3: 000000000dd36000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __local_bh_enable_ip+0xce/0x1c0 kernel/softirq.c:389 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_nc_purge_paths+0x318/0x3b0 net/batman-adv/network-coding.c:471 batadv_nc_worker+0x369/0x610 net/batman-adv/network-coding.c:722 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 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