INFO: task syz.0.16:5236 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.16 state:D stack:29088 pid: 5236 ppid: 4969 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 __fdget_pos+0x2bf/0x370 fs/file.c:1056 fdget_pos include/linux/file.h:76 [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:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f7e37018969 RSP: 002b:00007f7e36267038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 00007f7e37240080 RCX: 00007f7e37018969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 00007f7e3709aab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f7e37240080 R15: 00007ffdeaa59148 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 1 lock held by klogd/3550: #0: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475 2 locks held by getty/3947: #0: ffff88802c6a1098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc90002d032e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158 2 locks held by syz.0.16/5235: #0: ffff88807867d4f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff888070108298 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.0.16/5236: #0: ffff88807867d4f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.1.17/5260: #0: ffff88802a15dc70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff88805d4c8298 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.1.17/5261: #0: ffff88802a15dc70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.2.18/5283: #0: ffff888073cd05f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff8880701088f0 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.2.18/5284: #0: ffff888073cd05f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.3.19/5306: #0: ffff888029f54370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff88805d4c88f0 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.3.19/5307: #0: ffff888029f54370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.4.20/5341: #0: ffff888023bca5f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff888070108f48 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.4.20/5342: #0: ffff888023bca5f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.5.21/5370: #0: ffff888077b880f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff88805d4c8f48 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.5.21/5371: #0: ffff888077b880f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.6.22/5399: #0: ffff888078476d70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff8880701095a0 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.6.22/5400: #0: ffff888078476d70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.7.23/5427: #0: ffff88802377f270 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff88805d4c95a0 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.7.23/5428: #0: ffff88802377f270 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.8.24/5462: #0: ffff88802358c870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff888070109bf8 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.8.24/5463: #0: ffff88802358c870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 2 locks held by syz.9.25/5492: #0: ffff888077106370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff88807010a250 (&sb->s_type->i_mutex_key#21){.+.+}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 1 lock held by syz.9.25/5493: #0: ffff888077106370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe0f/0xe50 kernel/hung_task.c:369 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 498 Comm: kworker/u4:4 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:check_preemption_disabled+0x42/0x110 lib/smp_processor_id.c:55 Code: 65 8b 05 49 b7 58 76 65 8b 0d b2 11 59 76 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04 RSP: 0018:ffffc9000362f9c8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 785c96d3dc4f4300 RDX: 0000000000000000 RSI: ffffffff8a0b2b40 RDI: ffffffff8a59a880 RBP: ffffc9000362fb18 R08: dffffc0000000000 R09: fffffbfff1ff7a38 R10: fffffbfff1ff7a38 R11: 1ffffffff1ff7a37 R12: ffff88807e7847d8 R13: 1ffff920006c5f4c R14: 0000000000000246 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555586a235c8 CR3: 000000002375f000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:436 [inline] lock_acquire+0x1a7/0x3f0 kernel/locking/lockdep.c:5625 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:369 [inline] batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:446 batadv_nc_worker+0x327/0x5c0 net/batman-adv/network-coding.c:726 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287