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:28224 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: ffffffff8cb2e230 (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: ffffffff8cb2ea50 (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: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669
2 locks held by getty/4029:
#0: ffff88802ffc2098 (&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/0:3/4261:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003f17d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2562
3 locks held by kworker/1:4/4319:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900041e7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2562
3 locks held by kworker/1:5/4323:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004207d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2562
3 locks held by kworker/0:8/4345:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004287d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2562
3 locks held by kworker/0:9/4353:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900042a7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2562
3 locks held by kworker/u4:11/6047:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004b27d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
4 locks held by kworker/u4:25/11128:
#0: ffff88801761e938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000d7dfd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd49ed0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594
#3: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_delete_nets+0xd2/0x370 net/ipv4/ip_tunnel.c:1152
3 locks held by kworker/1:3/13737:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90004ad7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
#2: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2562
2 locks held by kworker/1:13/13746:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900057bfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
2 locks held by syz.5.6413/30550:
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506
#1: ffffffff8cb33578 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#1: ffffffff8cb33578 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
2 locks held by syz.1.6419/30570:
#0: ffffffff8d5b0e68 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0xdc/0x1b20 drivers/net/ppp/ppp_generic.c:727
#1: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: ppp_create_interface drivers/net/ppp/ppp_generic.c:3376 [inline]
#1: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1065 [inline]
#1: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8db/0x1b20 drivers/net/ppp/ppp_generic.c:731
1 lock held by syz.1.6419/30571:
#0: ffffffff8d5b0e68 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0xdc/0x1b20 drivers/net/ppp/ppp_generic.c:727
1 lock held by syz.6.6421/30577:
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506
2 locks held by syz.3.6422/30584:
#0: ffffffff8dd49ed0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x324/0x5b0 net/core/net_namespace.c:504
#1: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: register_nexthop_notifier+0x84/0x240 net/ipv4/nexthop.c:3619
1 lock held by syz.4.6424/30586:
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506
3 locks held by syz.4.6424/30587:
#0: ffffffff8ddb7a50 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:860
#1: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
#1: ffffffff8e06d568 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_cmd_new+0x6f5/0xb80 net/openvswitch/datapath.c:1839
#2: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: internal_dev_create+0x38a/0x550 net/openvswitch/vport-internal_dev.c:158
=============================================
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 07/24/2026
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: 15009 Comm: kworker/u4:51 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:101 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x62/0x290 mm/kasan/generic.c:189
Code: 00 00 fc ff df 49 89 fe 49 c1 ee 03 49 ba 00 00 00 00 00 fc ff df 4f 8d 1c 16 4c 8d 44 3e ff 4d 89 c1 49 c1 e9 03 4b 8d 1c 21 <49> 89 df 4d 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 4c
RSP: 0018:ffffc90004f97750 EFLAGS: 00000807
RAX: 0000000000000001 RBX: fffffbfff2166666 RCX: ffffffff8164beb4
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90b33328
RBP: 0000000000000002 R08: ffffffff90b3332f R09: 1ffffffff2166665
R10: dffffc0000000000 R11: fffffbfff2166665 R12: dffffc0000000001
R13: dffffc0000000000 R14: 1ffffffff2166665 R15: 000000000000075c
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555565bdc4e8 CR3: 000000007b1cb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: fffffffffffffffc DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
instrument_atomic_read include/linux/instrumented.h:72 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
hlock_class kernel/locking/lockdep.c:228 [inline]
mark_lock+0x94/0x320 kernel/locking/lockdep.c:4684
mark_held_locks kernel/locking/lockdep.c:4302 [inline]
__trace_hardirqs_on_caller kernel/locking/lockdep.c:4320 [inline]
lockdep_hardirqs_on_prepare+0x237/0x7c0 kernel/locking/lockdep.c:4387
trace_hardirqs_on+0x34/0x40 kernel/trace/trace_preemptirq.c:49
crng_make_state+0x4ee/0xb00 drivers/char/random.c:353
_get_random_bytes+0xfc/0x250 drivers/char/random.c:366
eth_random_addr include/linux/etherdevice.h:232 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:756 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
nsim_dev_trap_report_work+0x313/0xa80 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