INFO: task syz.4.3200:12597 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.3200 state:D stack:27120 pid:12597 tgid:12596 ppid:5587 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x16dc/0x5500 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578 nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1889 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7f5/0x990 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x565/0x870 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b7/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbd932de0d9 RSP: 002b:00007fbd91536028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fbd93565fa0 RCX: 00007fbd932de0d9 RDX: 0000000024004910 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007fbd93375024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbd93566038 R14: 00007fbd93565fa0 R15: 00007ffcb10f4a08 Showing all locks held in the system: 3 locks held by kworker/0:0/9: 2 locks held by kworker/u8:0/12: #0: ffff88813ff5c138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff88813ff5c138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #1: ffffc90000117c40 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc90000117c40 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 1 lock held by khungtaskd/37: #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:2/42: #0: ffff88813ff5c138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #0: ffff88813ff5c138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 #1: ffffc90000b37c40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline] #1: ffffc90000b37c40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405 2 locks held by getty/5337: #0: ffff8880365e30a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211 10 locks held by syz-executor/5582: 1 lock held by syz-executor/5585: #0: ffffffff8de0a0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:38 [inline] #0: ffffffff8de0a0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xdc/0x720 kernel/exit.c:1712 3 locks held by kworker/0:3/5593: 2 locks held by syz.2.1658/9339: #0: ffffffff8f61d720 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8e4e8ad8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x136/0x16e0 fs/nfsd/nfsctl.c:1964 2 locks held by syz.4.3200/12597: #0: ffffffff8f61d720 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8e4e8ad8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1889 1 lock held by syz-executor/13079: #0: ffffffff8de0a0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:38 [inline] #0: ffffffff8de0a0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xdc/0x720 kernel/exit.c:1712 3 locks held by syz.5.4535/15373: #0: ffffffff8f61d720 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffff888062c1e928 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xf4/0x7b0 net/netlink/af_netlink.c:2410 #2: ffffffff8e4e8ad8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_rpc_status_get_dumpit+0xdb/0x13f0 fs/nfsd/nfsctl.c:1510 2 locks held by syz.1.4558/15421: #0: ffffffff8f61d720 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8e4e8ad8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1c0/0x790 fs/nfsd/nfsctl.c:1754 1 lock held by syz-executor/15778: #0: ffffffff8de0a0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:38 [inline] #0: ffffffff8de0a0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xdc/0x720 kernel/exit.c:1712 1 lock held by syz-executor/15823: #0: ffffffff8de0a0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:38 [inline] #0: ffffffff8de0a0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xdc/0x720 kernel/exit.c:1712 6 locks held by syz.6.5115/16704: 3 locks held by syz.7.5143/16760: #0: ffff888033a7da78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] #0: ffff888033a7da78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:709 [inline] #0: ffff888033a7da78 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x82/0x220 net/socket.c:1501 #1: ffffffff8f61b660 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x54/0x90 kernel/notifier.c:379 #2: ffff88805d4a24c8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nft_rcv_nl_event+0x148/0xe60 net/netfilter/nf_tables_api.c:12094 4 locks held by syz.3.5144/16761: 1 lock held by syz.8.5142/16765: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 1509 Comm: kworker/u8:13 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_dat_purge RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x3a/0xb0 kernel/rcu/tree.c:752 Code: e8 3b 09 99 09 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 87 b3 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 3c a5 84 00 48 c7 c3 58 dd 9e 92 49 03 1e 48 89 RSP: 0018:ffffc90006857978 EFLAGS: 00000246 RAX: 1ffffffff1b670fa RBX: 0000000000000000 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8bca5960 RDI: ffffffff8bca5920 RBP: ffffffff8188621c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8e059220 R12: 0000000000000002 R13: ffffffff8e1c3000 R14: ffffffff8db387d0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125c46000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f69cf0356c8 CR3: 000000006a576000 CR4: 00000000003526f0 Call Trace: trace_lock_acquire include/trace/events/lock.h:23 [inline] lock_acquire+0x5f/0x350 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] __local_bh_disable_ip+0x205/0x420 kernel/softirq.c:174 local_bh_disable include/linux/bottom_half.h:20 [inline] spin_lock_bh include/linux/spinlock_rt.h:89 [inline] __batadv_dat_purge+0x124/0x400 net/batman-adv/distributed-arp-table.c:174 batadv_dat_purge+0x20/0x70 net/batman-adv/distributed-arp-table.c:205 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245