syzbot


INFO: task hung in ovs_dp_masks_rebalance (2)

Status: upstream: reported on 2026/04/14 04:54
Reported-by: syzbot+cbdbbcb231cdbc606959@syzkaller.appspotmail.com
First crash: 10d, last: 10d
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ovs_dp_masks_rebalance (7) openvswitch 1 5 450d 461d 0/29 auto-obsoleted due to no activity on 2025/04/28 19:38
upstream INFO: task hung in ovs_dp_masks_rebalance (3) openvswitch 1 1 1248d 1248d 0/29 auto-obsoleted due to no activity on 2023/04/22 10:20
upstream INFO: task hung in ovs_dp_masks_rebalance (2) openvswitch 1 68 1406d 1693d 0/29 auto-obsoleted due to no activity on 2022/10/15 22:59
upstream INFO: task hung in ovs_dp_masks_rebalance openvswitch 1 771 2058d 2101d 15/29 fixed on 2020/09/16 22:51
linux-6.1 INFO: task hung in ovs_dp_masks_rebalance 1 1 170d 170d 0/3 auto-obsoleted due to no activity on 2026/02/13 02:42
upstream INFO: task hung in ovs_dp_masks_rebalance (4) openvswitch 1 2 1015d 1035d 0/29 auto-obsoleted due to no activity on 2023/10/11 14:44
upstream INFO: task hung in ovs_dp_masks_rebalance (5) openvswitch 1 23 670d 702d 0/29 auto-obsoleted due to no activity on 2024/08/11 13:50
upstream INFO: task hung in ovs_dp_masks_rebalance (6) openvswitch 1 19 527d 581d 0/29 auto-obsoleted due to no activity on 2025/01/01 16:32

Sample crash report:
INFO: task kworker/0:6:14976 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:6     state:D stack:25168 pid:14976 ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x562/0xaf0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:0/7:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc900000c7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2df30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2e750 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
3 locks held by kworker/1:3/3653:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90002f87d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
2 locks held by getty/4029:
 #0: ffff88814d092098 (&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+0x429/0x1390 drivers/tty/n_tty.c:2198
2 locks held by kworker/0:3/4275:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003f37d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/1:4/4312:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004537d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/1:5/4314:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004547d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/0:7/4345:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc900045b7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/0:8/4348:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004577d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
5 locks held by kworker/u4:21/5039:
 #0: ffff888017616938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e47fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd3af10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594
 #3: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #3: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_exit_net+0xe1/0x7a0 net/openvswitch/datapath.c:2653
 #4: ffffffff8cb33140 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023
3 locks held by kworker/1:6/9059:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000546fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/0:1/13602:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003207d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/1:9/14166:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003637d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/0:4/14176:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc900038ffd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/1:11/14245:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003d9fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/1:12/14249:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003e57d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/1:13/14922:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003dd7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/0:6/14976:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003687d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/1:15/15158:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004657d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/1:16/15204:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000479fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/0:9/15606:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003eb7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/0:10/15709:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000488fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by syz-executor/15900:
 #0: ffff88802a91d468 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:526 [inline]
 #0: ffff88802a91d468 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x20e/0x500 net/bluetooth/hci_core.c:2731
 #1: ffff88802a91c428 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x45b/0xf40 net/bluetooth/hci_sync.c:5234
 #2: ffffffff8dea6268 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1829 [inline]
 #2: ffffffff8dea6268 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2504
3 locks held by kworker/0:11/16031:
3 locks held by kworker/0:12/16036:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003697d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
3 locks held by kworker/0:13/16101:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003397d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e05fbe8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2504
1 lock held by syz.9.3451/16710:
 #0: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #0: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
2 locks held by syz.2.3452/16719:
 #0: ffffffff8cb82668 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239
 #1: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #1: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
2 locks held by syz.7.3453/16729:
 #0: ffffffff96c51168 (&pmus_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff96c51168 (&pmus_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline]
 #0: ffffffff96c51168 (&pmus_srcu){....}-{0:0}, at: perf_init_event kernel/events/core.c:11664 [inline]
 #0: ffffffff96c51168 (&pmus_srcu){....}-{0:0}, at: perf_event_alloc+0xbe2/0x21b0 kernel/events/core.c:11990
 #1: ffffffff8cb82668 (event_mutex){+.+.}-{3:3}, at: perf_trace_init+0x4c/0x2d0 kernel/trace/trace_event_perf.c:221

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

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 03/18/2026
Call Trace:
 <TASK>
 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+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:__srcu_read_lock+0x2/0x80 kernel/rcu/srcutree.c:635
Code: 76 fe ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 24 ff ff ff 4c 89 ff e8 5b 77 67 00 e9 17 ff ff ff 66 0f 1f 44 00 00 41 57 <41> 56 53 48 89 fb 49 bf 00 00 00 00 00 fc ff df 48 81 c7 80 01 00
RSP: 0018:ffffc90000146898 EFLAGS: 00000082
RAX: 0000000080000300 RBX: 0000000000000000 RCX: ffffffff8188e20d
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8cb742e0
RBP: ffffc90000146970 R08: ffffffff8e1ff26f R09: 1ffffffff1c3fe4d
R10: dffffc0000000000 R11: fffffbfff1c3fe4e R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff814f6627 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4704af0d58 CR3: 000000008c7bc000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 srcu_read_lock_notrace include/linux/srcu.h:175 [inline]
 trace_irq_disable_rcuidle+0x98/0x140 include/trace/events/preemptirq.h:36
 __local_bh_enable_ip+0xd7/0x1c0 kernel/softirq.c:403
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 ip6_pol_route+0xe37/0x12a0 net/ipv6/route.c:2298
 pol_lookup_func include/net/ip6_fib.h:579 [inline]
 fib6_rule_lookup+0x208/0x5d0 net/ipv6/fib6_rules.c:116
 ip6_route_input_lookup net/ipv6/route.c:2329 [inline]
 ip6_route_input+0x725/0xa40 net/ipv6/route.c:2625
 ip6_rcv_finish+0x13f/0x230 net/ipv6/ip6_input.c:77
 ip_sabotage_in+0x1f0/0x270 net/bridge/br_netfilter_hooks.c:1001
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_slow+0xb9/0x200 net/netfilter/core.c:614
 nf_hook include/linux/netfilter.h:257 [inline]
 NF_HOOK+0x219/0x3b0 include/linux/netfilter.h:300
 __netif_receive_skb_one_core net/core/dev.c:5619 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5733
 netif_receive_skb_internal net/core/dev.c:5819 [inline]
 netif_receive_skb+0x1d4/0x830 net/core/dev.c:5878
 NF_HOOK+0x9a/0x390 include/linux/netfilter.h:302
 br_handle_frame_finish+0x1263/0x16f0 net/bridge/br_input.c:204
 br_nf_hook_thresh+0x3c9/0x4a0 net/bridge/br_netfilter_hooks.c:1184
 br_nf_pre_routing_finish_ipv6+0x9da/0xd00 net/bridge/br_netfilter_ipv6.c:-1
 NF_HOOK include/linux/netfilter.h:302 [inline]
 br_nf_pre_routing_ipv6+0x345/0x6b0 net/bridge/br_netfilter_ipv6.c:243
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:260 [inline]
 br_handle_frame+0x1167/0x13c0 net/bridge/br_input.c:406
 __netif_receive_skb_core+0x1004/0x38f0 net/core/dev.c:5513
 __netif_receive_skb_one_core net/core/dev.c:5617 [inline]
 __netif_receive_skb+0x74/0x290 net/core/dev.c:5733
 process_backlog+0x38d/0x6f0 net/core/dev.c:6061
 __napi_poll+0xc0/0x460 net/core/dev.c:6628
 napi_poll net/core/dev.c:6695 [inline]
 net_rx_action+0x5dd/0xb20 net/core/dev.c:6809
 handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
 run_ksoftirqd+0xa4/0x100 kernel/softirq.c:968
 smpboot_thread_fn+0x64a/0xa40 kernel/smpboot.c:164
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/14 04:53 linux-6.1.y 8e8fc038cad5 1a086e7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in ovs_dp_masks_rebalance
* Struck through repros no longer work on HEAD.