INFO: task rcu_tasks_kthre:11 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:rcu_tasks_kthre state:D stack:27824 pid: 11 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85 __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x48/0x60 kernel/sched/completion.c:138 __synchronize_srcu+0x2b5/0x350 kernel/rcu/srcutree.c:930 rcu_tasks_wait_gp+0x43b/0x8e0 kernel/rcu/tasks.h:327 rcu_tasks_kthread+0x2c1/0x640 kernel/rcu/tasks.h:226 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8d11efa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by getty/3947: #0: ffff88802d35a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158 4 locks held by kworker/1:36/19430: 3 locks held by dhcpcd-run-hook/24120: ============================================= 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 10/07/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 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+0xe1b/0xe60 kernel/hung_task.c:369 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 19430 Comm: kworker/1:36 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Workqueue: rcu_gp process_srcu RIP: 0010:__lock_acquire+0xddb/0x7d40 kernel/locking/lockdep.c:5090 Code: 00 00 00 e8 67 a8 00 00 85 c0 0f 84 4e 09 00 00 48 c7 c0 80 df 14 97 48 c1 e8 03 49 b8 00 00 00 00 00 fc ff df 42 0f b6 04 00 <84> c0 0f 85 43 0e 00 00 4c 89 a4 24 a8 00 00 00 83 3d 3e d8 b7 15 RSP: 0018:ffffc9000369f600 EFLAGS: 00000806 RAX: 0000000000000004 RBX: ffff88802b66e410 RCX: ffffffff815db004 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff910470d0 RBP: ffffc9000369f848 R08: dffffc0000000000 R09: 1ffffffff2208e1a R10: dffffc0000000000 R11: fffffbfff2208e1b R12: ffff88802b66e414 R13: ffff88802b66d940 R14: ffff88802b66e480 R15: ffff88802b66e4a0 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055697734e008 CR3: 000000005e514000 CR4: 00000000003506e0 DR0: 0000200000000600 DR1: 0000200000000300 DR2: 0000200000000300 DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737 __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 srcu_advance_state kernel/rcu/srcutree.c:1177 [inline] process_srcu+0x2f/0xca0 kernel/rcu/srcutree.c:1325 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287