INFO: task rcu_tasks_kthre:12 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:27728 pid:12 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x2c2/0x590 kernel/sched/completion.c:138
__synchronize_srcu+0x2b3/0x350 kernel/rcu/srcutree.c:1243
rcu_tasks_wait_gp+0x49f/0xac0 kernel/rcu/tasks.h:693
rcu_tasks_one_gp+0xd27/0xef0 kernel/rcu/tasks.h:534
rcu_tasks_kthread+0x6e/0x90 kernel/rcu/tasks.h:562
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e170 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2e990 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2d7e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2d7e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2d7e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6529
2 locks held by getty/4028:
#0: ffff88814d308098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
3 locks held by kworker/0:5/11862:
#0: ffff88814c89b938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003787d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4138
2 locks held by kworker/0:1/22228:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003acfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/u4:47/26094:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003aa7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
2 locks held by syz.5.16528/28778:
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506
#1: ffffffff8cb334b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#1: ffffffff8cb334b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.8.16537/28796:
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
1 lock held by syz.2.16540/28803:
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
3 locks held by syz.6.16542/28813:
#0: ffffffff8ddb5b90 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:860
#1: ffffffff8ddb59a8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
#1: ffffffff8ddb59a8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x107/0x790 net/netlink/genetlink.c:848
#2: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: __tipc_nl_compat_doit net/tipc/netlink_compat.c:366 [inline]
#2: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: tipc_nl_compat_doit+0x224/0x610 net/tipc/netlink_compat.c:401
1 lock held by syz.3.16544/28820:
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3118
1 lock held by syz.3.16544/28821:
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506
1 lock held by syz.3.16544/28822:
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x54d/0xe80 net/core/dev_ioctl.c:571
1 lock held by syz.3.16544/28824:
#0: ffffffff8dd550a8 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x54d/0xe80 net/core/dev_ioctl.c:571
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 26099 Comm: kworker/u4:51 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:lockdep_softirqs_off+0xa/0x430 kernel/locking/lockdep.c:4475
Code: c7 c7 28 e9 20 8e e8 35 a6 6f 00 48 ba 00 00 00 00 00 fc ff df e9 04 fe ff ff 66 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 <41> 54 53 48 83 e4 e0 48 81 ec 80 00 00 00 65 48 8b 04 25 28 00 00
RSP: 0018:ffffc90003affa78 EFLAGS: 00000046
RAX: 0000000080000003 RBX: 0000000000000201 RCX: 0000000000000000
RDX: 0000000000000040 RSI: 0000000000000201 RDI: ffffffff8618b7f0
RBP: ffffc90003affa90 R08: ffffc90003affa9f R09: ffffc90003affa60
R10: dffffc0000000000 R11: fffff5200075ff54 R12: 1ffff9200075ff54
R13: ffff888025f16a48 R14: 0000000000000246 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe86d70ca4 CR3: 000000005d171000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
__local_bh_disable_ip+0xb6/0x1a0 kernel/softirq.c:361
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:125 [inline]
_raw_spin_lock_bh+0x18/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:816 [inline]
nsim_dev_trap_report_work+0x680/0xa80 drivers/net/netdevsim/dev.c:851
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295