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: 114d, last: 37d
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 554d 565d 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 1352d 1352d 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 1510d 1797d 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 2162d 2205d 15/29 fixed on 2020/09/16 22:51
linux-6.1 INFO: task hung in ovs_dp_masks_rebalance 1 1 274d 274d 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 1119d 1139d 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 775d 806d 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 631d 685d 0/29 auto-obsoleted due to no activity on 2025/01/01 16:32

Sample crash report:
INFO: task kworker/0:4:4318 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4     state:D stack:24000 pid:4318  ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 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+0x548/0xae0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
 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
 </TASK>
INFO: task kworker/0:1:23755 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1     state:D stack:25120 pid:23755 ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 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+0x548/0xae0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
 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
 </TASK>
INFO: task kworker/0:14:26064 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:14    state:D stack:25136 pid:26064 ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 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+0x548/0xae0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
 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
 </TASK>
INFO: task kworker/0:16:26066 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:16    state:D stack:24304 pid:26066 ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 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+0x548/0xae0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
 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
 </TASK>
INFO: task kworker/0:18:26070 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:18    state:D stack:25136 pid:26070 ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 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+0x548/0xae0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
 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
 </TASK>
INFO: task kworker/0:20:26076 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:20    state:D stack:23664 pid:26076 ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 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+0x548/0xae0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
 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
 </TASK>
INFO: task kworker/0:21:26325 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:21    state:D stack:28912 pid:26325 ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 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+0x548/0xae0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
 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
 </TASK>
INFO: task kworker/0:23:26330 blocked for more than 147 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:23    state:D stack:25232 pid:26330 ppid:2      flags:0x00004000
Workqueue: events ovs_dp_masks_rebalance
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x107f/0x4030 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+0x548/0xae0 kernel/locking/mutex.c:747
 ovs_lock net/openvswitch/datapath.c:107 [inline]
 ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
 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
 </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+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900000c7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e4f0 (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: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by ksoftirqd/0/15:
1 lock held by khungtaskd/27:
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
3 locks held by kworker/0:2/127:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90002db7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
2 locks held by getty/4030:
 #0: ffff88814d475098 (&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/1:4/4315:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000461fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:4/4318:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000465fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
2 locks held by kworker/u4:18/10274:
6 locks held by kworker/u4:20/10278:
 #0: ffff888017616938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003877d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd3c650 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594
 #3: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #3: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_exit_net+0xe1/0x7a0 net/openvswitch/datapath.c:2685
 #4: ffffffff8dd494e8 (rtnl_mutex){+.+.}-{3:3}, at: internal_dev_destroy+0xef/0x1a0 net/openvswitch/vport-internal_dev.c:184
 #5: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #5: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
3 locks held by kworker/0:5/11576:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90005d4fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:5/15644:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003f07d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:9/15646:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004a7fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:11/15648:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004a9fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:23/15662:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004b67d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:26/15667:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004b97d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:7/17824:
 #0: 
ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90005587d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:1/23755:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900044b7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:6/24364:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900055f7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:9/24931:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900034ffd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:10/26060:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e90fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:12/26061:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e91fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:0/26062:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e92fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:13/26063:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e93fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:14/26064:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e94fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:15/26065:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e95fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:16/26066:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e96fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
2 locks held by kworker/0:17/26067:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e97fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/1:1/26068:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e98fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:18/26070:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e99fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:3/26071:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e9afd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:20/26076:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000d42fd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:7/26084:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900045bfd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:8/26085:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90005197d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:21/26325:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900036ffd00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:12/26328:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900037e7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:13/26329:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900038c7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/0:23/26330:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900038d7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:15/26866:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003bc7d00 ((work_completion)(&(&ovs_net->masks_rebalance)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_lock net/openvswitch/datapath.c:107 [inline]
 #2: ffffffff8e0614a8 (ovs_mutex){+.+.}-{3:3}, at: ovs_dp_masks_rebalance+0x2b/0xd0 net/openvswitch/datapath.c:2536
3 locks held by kworker/1:16/27263:
 #0: ffff88814caafd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003c37d00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd494e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x15/0x30 net/ipv6/addrconf.c:4672
1 lock held by syz.0.7485/29343:
 #0: ffffffff8cb33700 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x5e0 kernel/rcu/tree.c:4023

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

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 05/09/2026
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+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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10260 Comm: kworker/u4:13 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:ksoftirqd_running kernel/softirq.c:95 [inline]
RIP: 0010:do_softirq+0xf9/0x210 kernel/softirq.c:496
Code: db 08 65 48 8b 3d 5f 39 b3 7e f6 c3 41 0f 95 c0 48 85 ff 0f 94 c1 08 c1 75 26 48 8d 5f 18 48 89 d8 48 c1 e8 03 42 0f b6 04 30 <84> c0 0f 85 df 00 00 00 83 3b 00 75 09 e8 45 22 07 00 84 c0 74 48
RSP: 0018:ffffc90003767a00 EFLAGS: 00000802
RAX: 0000000000000000 RBX: ffff88813fef3c18 RCX: 45611a8a1e390400
RDX: dffffc0000000000 RSI: ffffffff8a8b0d60 RDI: ffff88813fef3c00
RBP: ffffc90003767ab0 R08: ffff888043d94a83 R09: 1ffff110087b2950
R10: dffffc0000000000 R11: ffffed10087b2951 R12: 0000000000000046
R13: ffff888026a17350 R14: dffffc0000000000 R15: 1ffff920006ecf40
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555576de94e8 CR3: 0000000073b5c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000008 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 __local_bh_enable_ip+0x180/0x1c0 kernel/softirq.c:421
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_nc_purge_paths+0x305/0x3a0 net/batman-adv/network-coding.c:471
 batadv_nc_worker+0x35f/0x600 net/batman-adv/network-coding.c:722
 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
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/30 13:07 linux-6.1.y fdb6fcb41cc7 fff8d0a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in ovs_dp_masks_rebalance
2026/05/14 02:39 linux-6.1.y ad16b162f21d 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in ovs_dp_masks_rebalance
2026/05/12 05:54 linux-6.1.y ad16b162f21d d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in ovs_dp_masks_rebalance
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.