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:28400 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
3 locks held by kworker/u4:3/156:
#0: ffff888017879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc90001fc7d00 ((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 getty/3949:
#0: ffff88802d2b7098 (&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/1:35/5109:
2 locks held by kworker/0:24/6728:
#0: ffff888017872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000431fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
1 lock held by syz.6.4232/23166:
#0: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
#0: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845
1 lock held by syz.6.4252/23238:
#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 lock held by syz.0.4251/23240:
#0: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x534/0xe30 net/core/dev_ioctl.c:571
2 locks held by syz.7.4254/23244:
#0: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
#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.3.4255/23247:
#0: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x5ce/0xe30 net/core/dev_ioctl.c:596
1 lock held by syz.3.4255/23248:
#0: ffffffff8e26ca48 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x5ce/0xe30 net/core/dev_ioctl.c:596
=============================================
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 10/15/2026
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3550 Comm: klogd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline]
RIP: 0010:mark_lock+0x9c/0x320 kernel/locking/lockdep.c:4642
Code: 89 c7 41 81 e7 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 c0 70 04 91 be 08 00 00 00 e8 4c c7 60 00 4c 0f a3 3d b4 c0 a6 0f <73> 10 49 69 c7 d0 00 00 00 4c 8d b8 80 ef 9a 90 eb 24 48 c7 c0 80
RSP: 0018:ffffc90002e4f980 EFLAGS: 00000057
RAX: 0000000000000001 RBX: ffff88807de85940 RCX: ffffffff815db004
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff910470f0
RBP: 0000000000000007 R08: ffffffff910470f7 R09: 1ffffffff2208e1e
R10: dffffc0000000000 R11: fffffbfff2208e1f R12: 0000000000000080
R13: dffffc0000000000 R14: ffff88807de86430 R15: 000000000000019b
FS: 00007f142f5e9c80(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555647be4e8 CR3: 000000002bd31000 CR4: 00000000003506e0
DR0: 0000200000002040 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
mark_usage kernel/locking/lockdep.c:-1 [inline]
__lock_acquire+0x1233/0x7d40 kernel/locking/lockdep.c:5074
lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737
__might_fault+0xb3/0x110 mm/memory.c:5357
rseq_get_rseq_cs_ptr_val kernel/rseq.c:131 [inline]
rseq_get_rseq_cs kernel/rseq.c:153 [inline]
rseq_ip_fixup kernel/rseq.c:266 [inline]
__rseq_handle_notify_resume+0x143/0xf40 kernel/rseq.c:314
rseq_handle_notify_resume include/linux/sched.h:2218 [inline]
tracehook_notify_resume include/linux/tracehook.h:201 [inline]
exit_to_user_mode_loop+0xe5/0x130 kernel/entry/common.c:184
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:217
__syscall_exit_to_user_mode_work kernel/entry/common.c:299 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:310
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f142f739407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fffd60fb910 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: 000000000000004c RBX: 00007f142f5e9c80 RCX: 00007f142f739407
RDX: 000000000000004c RSI: 00007fffd60fba50 RDI: 0000000000000003
RBP: 00007fffd60fbe80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007fffd60fbe98
R13: 00007fffd60fba50 R14: 0000000000000031 R15: 00007fffd60fba50