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:27760 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/3945: #0: ffff88814d0f9098 (&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/0:0/28937: ============================================= 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 10/15/2026 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 28937 Comm: kworker/0:0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 Workqueue: rcu_gp process_srcu RIP: 0010:delay_tsc+0x57/0xc0 arch/x86/lib/delay.c:79 Code: 90 49 89 d7 49 c1 e7 20 49 09 c7 4d 29 f7 49 39 df 73 53 bf 01 00 00 00 e8 f6 1f 43 fd 65 8b 05 c7 30 f3 7b 85 c0 74 1c f3 90 01 00 00 00 e8 4f 1e 43 fd e8 ba 5c ba 05 39 c5 75 0e 0f 01 f9 RSP: 0018:ffffc900031afac0 EFLAGS: 00000286 RAX: 0000000080000000 RBX: 0000000000002af9 RCX: 0000000000000000 RDX: 0000000000000391 RSI: ffffffff8a7a50e0 RDI: 00000000ffffffff RBP: 0000000000000000 R08: ffffc900031af927 R09: 1ffff92000635f24 R10: dffffc0000000000 R11: fffff52000635f25 R12: dffffc0000000000 R13: ffffffff8d11faa0 R14: 0000039118e18850 R15: 00000000000017b1 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbd4563d2f8 CR3: 000000001bbaf000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00002000000001c0 DR3: 00002000000001c0 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: try_check_zero+0x2cb/0x340 kernel/rcu/srcutree.c:702 srcu_advance_state kernel/rcu/srcutree.c:1227 [inline] process_srcu+0x1b6/0xca0 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