INFO: task syz.4.635:6462 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.635       state:D stack:27152 pid: 6462 ppid:  4194 flags:0x00004004
Call Trace:
 <TASK>
 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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 nfsd_nrthreads+0x48/0xe0 fs/nfsd/nfssvc.c:280
 write_threads+0x1ec/0x350 fs/nfsd/nfsctl.c:430
 nfsctl_transaction_write+0x105/0x150 fs/nfsd/nfsctl.c:114
 vfs_write+0x304/0xd70 fs/read_write.c:592
 ksys_write+0x153/0x260 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6692ab21d9
RSP: 002b:00007f6690d0a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6692d39fa0 RCX: 00007f6692ab21d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000b
RBP: 00007f6692b49888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6692d3a038 R14: 00007f6692d39fa0 R15: 00007ffe0bca3b78
 </TASK>
INFO: task syz.4.635:6463 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.635       state:D stack:27216 pid: 6463 ppid:  4194 flags:0x00004004
Call Trace:
 <TASK>
 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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 __fdget_pos+0x2bf/0x370 fs/file.c:1056
 fdget_pos include/linux/file.h:77 [inline]
 ksys_write+0x77/0x260 fs/read_write.c:638
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6692ab21d9
RSP: 002b:00007f6690ce9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6692d3a090 RCX: 00007f6692ab21d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000b
RBP: 00007f6692b49888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6692d3a128 R14: 00007f6692d3a090 R15: 00007ffe0bca3b78
 </TASK>
INFO: task syz.4.635:6467 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.635       state:D stack:29040 pid: 6467 ppid:  4194 flags:0x00004004
Call Trace:
 <TASK>
 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_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 __mutex_lock_common+0xdf5/0x2400 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 __fdget_pos+0x2bf/0x370 fs/file.c:1056
 fdget_pos include/linux/file.h:77 [inline]
 ksys_write+0x77/0x260 fs/read_write.c:638
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6692ab21d9
RSP: 002b:00007f6690ca7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6692d3a270 RCX: 00007f6692ab21d9
RDX: 0000000000000005 RSI: 0000200000000280 RDI: 0000000000000008
RBP: 00007f6692b49888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6692d3a308 R14: 00007f6692d3a270 R15: 00007ffe0bca3b78
 </TASK>

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/1:2/1108:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000452fd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74
2 locks held by getty/3944:
 #0: ffff88802cf84098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
4 locks held by kworker/u4:12/4324:
 #0: ffff8880179cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc900012efd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8e241690 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
 #3: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: cangw_pernet_exit+0xe/0x20 net/can/gw.c:1279
2 locks held by kworker/1:17/5922:
 #0: ffff888017872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000322fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
3 locks held by syz.4.635/6462:
 #0: ffff8880773de870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff88805ac04460 (sb_writers#37){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffffffff8d3713a8 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nrthreads+0x48/0xe0 fs/nfsd/nfssvc.c:280
1 lock held by syz.4.635/6463:
 #0: ffff8880773de870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
3 locks held by syz.4.635/6466:
 #0: ffff88801eaccaf0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff88805ac04460 (sb_writers#37){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffffffff8d3713a8 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb3/0xb80 fs/nfsd/nfsctl.c:848
1 lock held by syz.4.635/6467:
 #0: ffff88801eaccaf0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
3 locks held by kworker/u4:15/7491:
 #0: ffff888017879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90003d7fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
1 lock held by syz.3.1389/8690:
3 locks held by kworker/0:11/8924:
 #0: ffff88802bd6a938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90003e9fd00 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4672
1 lock held by syz.0.1557/9189:
 #0: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x8dd/0xac0 net/core/dev.c:10722
2 locks held by syz.0.1557/9193:
 #0: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8e24d5c8 (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
2 locks held by syz.5.1559/9197:
 #0: ffffffff8e2aa550 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
 #1: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: nl80211_pre_doit+0x28/0x540 net/wireless/nl80211.c:14971
1 lock held by syz.2.1562/9206:
 #0: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz.3.1564/9209:
 #0: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz.1.1566/9213:
 #0: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8e24d5c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695

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

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 09/16/2026
Call Trace:
 <TASK>
 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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4286 Comm: kworker/u4:6 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:mark_held_locks kernel/locking/lockdep.c:4248 [inline]
RIP: 0010:__trace_hardirqs_on_caller kernel/locking/lockdep.c:4278 [inline]
RIP: 0010:lockdep_hardirqs_on_prepare+0x1c0/0x7c0 kernel/locking/lockdep.c:4345
Code: 10 00 74 05 e8 01 b1 61 00 4c 89 b3 c8 0a 00 00 48 c7 c7 e0 39 2b 8a e8 6e 70 65 08 65 ff 05 47 c1 a5 7e 48 8d b3 e8 0a 00 00 <49> 89 f6 49 c1 ee 03 48 ba 00 00 00 00 00 fc ff df 41 0f b6 04 16
RSP: 0018:ffffc9000328f9e0 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff88802b279dc0 RCX: 6ff4d30b91a8ed00
RDX: dffffc0000000000 RSI: ffff88802b27a8a8 RDI: ffffffff8a7a4c00
RBP: ffffc9000328faa0 R08: ffff88807c711d03 R09: 1ffff1100f8e23a0
R10: dffffc0000000000 R11: ffffed100f8e23a1 R12: ffffffff8996dcc5
R13: 0000000000000000 R14: 3c2807179fe6f01a R15: 1ffff92000651f58
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555673724e8 CR3: 000000002abcf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 trace_hardirqs_on+0x67/0x80 kernel/trace/trace_preemptirq.c:49
 __local_bh_enable_ip+0x136/0x1c0 kernel/softirq.c:406
 spin_unlock_bh include/linux/spinlock.h:409 [inline]
 batadv_nc_purge_paths+0x305/0x3a0 net/batman-adv/network-coding.c:475
 batadv_nc_worker+0x321/0x5c0 net/batman-adv/network-coding.c:726
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>