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:27440 pid:   11 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 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
 </TASK>

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/3957:
 #0: ffff88814ce28098 (&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+0x594/0x1a50 drivers/tty/n_tty.c:2158
3 locks held by kworker/u4:6/4959:
2 locks held by kworker/u4:20/30741:
2 locks held by kworker/1:132/12416:
 #0: ffff888017872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc900043bfd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
3 locks held by syz.9.13108/25418:
 #0: ffffffff8e260ad0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x324/0x5b0 net/core/net_namespace.c:499
 #1: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: sit_exit_batch_net+0xd9/0x4e0 net/ipv6/sit.c:1918
 #2: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #2: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
3 locks held by syz.3.13111/25431:
2 locks held by syz.2.13112/25446:

=============================================

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:
 <TASK>
 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
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12422 Comm: kworker/1:137 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:__preempt_count_add kernel/rcu/tree.c:1119 [inline]
RIP: 0010:rcu_is_watching+0x4/0xa0 kernel/rcu/tree.c:1122
Code: 3b 44 24 70 75 1b 48 8d 65 e8 5b 41 5e 41 5f 5d c3 e8 00 c2 64 08 41 f7 c7 00 02 00 00 75 bd eb bc e8 e0 c1 64 08 41 57 41 56 <53> 65 ff 05 4c a6 9d 7e e8 4f d2 64 08 89 c3 83 f8 08 73 5c 49 bf
RSP: 0018:ffffc9000441fb08 EFLAGS: 00000257
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff815cf4c5
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e6d3228
RBP: ffffc9000441fc28 R08: ffffffff8e6d322f R09: 1ffffffff1cda645
R10: dffffc0000000000 R11: fffffbfff1cda646 R12: 1ffff92000883f70
R13: ffff888017872138 R14: 0000000000000001 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f141917b2f8 CR3: 000000007950d000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000200000000940 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0xc7/0x400 kernel/locking/lockdep.c:5708
 process_one_work+0x795/0xff0 kernel/workqueue.c:2285
 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
 </TASK>