INFO: task syz.0.17:5073 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:29184 pid:5073 ppid:4868 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747 __fdget_pos+0x2ae/0x360 fs/file.c:1038 fdget_pos include/linux/file.h:74 [inline] __do_sys_getdents64 fs/readdir.c:365 [inline] __se_sys_getdents64+0xbe/0x260 fs/readdir.c:354 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f053b78eec9 RSP: 002b:00007f053c5dd038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 00007f053b9e6090 RCX: 00007f053b78eec9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 00007f053b811f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f053b9e6128 R14: 00007f053b9e6090 R15: 00007fff1d70eb38 Showing all locks held in the system: 3 locks held by kworker/u4:0/9: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/27: #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 5 locks held by kworker/u4:5/1189: #0: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 #1: ffff8880b8f27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999 #2: ffff8880b8f28418 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999 #3: ffffffff96e7a338 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x6a/0x490 lib/debugobjects.c:698 #4: ffffffff96e2bb70 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_check_no_obj_freed lib/debugobjects.c:968 [inline] #4: ffffffff96e2bb70 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_check_no_obj_freed+0x136/0x530 lib/debugobjects.c:1009 2 locks held by getty/4027: #0: ffff88802fbda098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198 1 lock held by kworker/0:6/4328: #0: ffff8880b8e3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 2 locks held by syz.0.17/5069: #0: ffff88807e742868 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff888068bb8150 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.0.17/5073: #0: ffff88807e742868 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 2 locks held by syz.1.18/5190: #0: ffff888078bd1268 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff888068968150 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.1.18/5191: #0: ffff888078bd1268 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 2 locks held by syz.2.19/5213: #0: ffff888026bdb768 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff888068bb8728 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.2.19/5214: #0: ffff888026bdb768 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 2 locks held by syz.3.20/5241: #0: ffff888026ac3c68 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff888068968728 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.3.20/5243: #0: ffff888026ac3c68 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 2 locks held by syz.4.22/5273: #0: ffff88807cd58ae8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff888068bb8d00 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.4.22/5274: #0: ffff88807cd58ae8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 2 locks held by syz.5.23/5302: #0: ffff88802646f768 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff888068bb92d8 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.5.23/5303: #0: ffff88802646f768 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 2 locks held by syz.6.24/5331: #0: ffff88807951f4e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff888068968d00 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.6.24/5333: #0: ffff88807951f4e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 2 locks held by syz.7.25/5366: #0: ffff888026bfe368 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff888068bb98b0 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.7.25/5367: #0: ffff888026bfe368 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 2 locks held by syz.8.26/5395: #0: ffff88807c41cd68 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 #1: ffff8880689692d8 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.8.26/5396: #0: ffff88807c41cd68 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 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+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 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: 9 Comm: kworker/u4:0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:lock_acquire+0xf0/0x490 kernel/locking/lockdep.c:5635 Code: 06 4a 8d 3c f5 28 77 1f 8e be 08 00 00 00 e8 87 ff 6d 00 4c 0f a3 25 e7 84 bc 0c 73 0d e8 f8 1b 08 00 84 c0 0f 84 18 02 00 00 <48> c7 c0 e4 ab 1f 8e 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 07 02 RSP: 0018:ffffc900000e7a40 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0216f0b600a31400 RDX: 0000000000000000 RSI: ffffffff8adefcc0 RDI: ffffffff8adefc80 RBP: ffffc900000e7b58 R08: dffffc0000000000 R09: fffffbfff1c3eee6 R10: fffffbfff1c3eee6 R11: 1ffffffff1c3eee5 R12: 0000000000000001 R13: 1ffff9200001cf54 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556c7245c8 CR3: 000000002f240000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] batadv_nc_process_nc_paths+0xdb/0x390 net/batman-adv/network-coding.c:687 batadv_nc_worker+0x425/0x600 net/batman-adv/network-coding.c:728 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295