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:28048 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/3945:
 #0: ffff88802da2c098 (&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/0:9/4373:
3 locks held by kworker/0:26/4397:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000390fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #2: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845
4 locks held by kworker/u4:8/6292:
3 locks held by kworker/u4:16/6310:
3 locks held by kworker/u4:21/6327:
 #0: ffff888017879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90003bafd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
2 locks held by kworker/1:25/7826:
 #0: ffff888017872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90004d8fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
3 locks held by kworker/0:37/8026:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90004d1fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d123930 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4c0 kernel/rcu/tree.c:4043
3 locks held by kworker/0:50/8053:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000536fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d123930 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4c0 kernel/rcu/tree.c:4043
1 lock held by syz.5.3318/18529:
 #0: ffffffff8d16c808 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239
2 locks held by syz.5.3318/18539:
 #0: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline]
 #0: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3454
 #1: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
1 lock held by syz.0.3319/18533:
 #0: ffffffff8d16c808 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239
1 lock held by syz.2.3322/18544:
 #0: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1f30 drivers/net/tun.c:3066
2 locks held by syz.2.3322/18546:
 #0: ffffffff8daf9828 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0xdc/0x1a70 drivers/net/ppp/ppp_generic.c:739
 #1: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: ppp_create_interface drivers/net/ppp/ppp_generic.c:3363 [inline]
 #1: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1073 [inline]
 #1: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8b2/0x1a70 drivers/net/ppp/ppp_generic.c:743
1 lock held by syz.2.3322/18550:
 #0: ffffffff8daf9828 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0xdc/0x1a70 drivers/net/ppp/ppp_generic.c:739

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

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 11/06/2026
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8026 Comm: kworker/0:37 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
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 <bf> 01 00 00 00 e8 4f 1e 43 fd e8 ba 5c ba 05 39 c5 75 0e 0f 01 f9
RSP: 0018:ffffc90004d1fac0 EFLAGS: 00000286
RAX: 0000000080000000 RBX: 0000000000002af9 RCX: 0000000000000000
RDX: 000000000000012b RSI: ffffffff8a7a50e0 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: ffffc90004d1f927 R09: 1ffff920009a3f24
R10: dffffc0000000000 R11: fffff520009a3f25 R12: dffffc0000000000
R13: ffffffff8d11faa0 R14: 0000012b8f984283 R15: 0000000000002ab8
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555d15149a38 CR3: 000000001b3df000 CR4: 00000000003506f0
DR0: 00002000000002c0 DR1: 0000200000000500 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 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
 </TASK>