syzbot

INFO: task syz.5.2553:16245 blocked for more than 144 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.2553      state:D stack:25800 pid:16245 tgid:16244 ppid:6385   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc69/0x1ca0 kernel/locking/mutex.c:776
 nfsd_nl_listener_get_doit+0x13e/0x7b0 fs/nfsd/nfsctl.c:2036
 genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
 __sys_sendmsg+0x16d/0x220 net/socket.c:2678
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f437018f749
RSP: 002b:00007f4370f70038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f43703e5fa0 RCX: 00007f437018f749
RDX: 000000002400e844 RSI: 0000200000000140 RDI: 0000000000000005
RBP: 00007f4370213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f43703e6038 R14: 00007f43703e5fa0 R15: 00007fff36c2c198
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e3c96a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e3c96a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8e3c96a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:6/217:
 #0: ffff888145aa0148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232
 #1: ffffc90003127c90 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233
 #2: ffff88807c766c70 (&sqd->lock){+.+.}-{4:4}, at: io_sq_thread_park+0x44/0x160 io_uring/sqpoll.c:56
2 locks held by getty/5577:
 #0: ffff888035e2d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x1510 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5819:
4 locks held by kworker/u8:24/7381:
 #0: ffff88801badc948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232
 #1: ffffc90004abfc90 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233
 #2: ffffffff9012bb90 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x830 net/core/net_namespace.c:670
 #3: ffffffff90142368 (rtnl_mutex){+.+.}-{4:4}, at: cfg802154_pernet_exit+0x17/0xe0 net/ieee802154/core.c:351
2 locks held by syz.3.2317/15252:
 #0: ffffffff901e89d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
 #1: ffffffff8e802148 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1886
2 locks held by syz.5.2553/16245:
 #0: ffffffff901e89d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
 #1: ffffffff8e802148 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_get_doit+0x13e/0x7b0 fs/nfsd/nfsctl.c:2036
2 locks held by syz-executor/18449:
4 locks held by syz.7.3087/18592:
3 locks held by syz.6.3089/18609:
1 lock held by iou-sqp-18610/18611:
1 lock held by cmp/18614:
4 locks held by syz.1.3091/18617:
2 locks held by syz.1.3091/18618:
 #0: ffff8880258834d8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_valid_genid+0x35/0x140 net/netfilter/nf_tables_api.c:11559
 #1: ffffffff8e3d4df8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311
3 locks held by syz.1.3091/18619:
 #0: ffff88805825d848 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
 #0: ffff88805825d848 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:661
 #1: ffffffff901e65f0 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain kernel/notifier.c:379 [inline]
 #1: ffffffff901e65f0 ((netlink_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x53/0xa0 kernel/notifier.c:368
 #2: ffff8880258834d8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nft_rcv_nl_event+0x187/0x6c0 net/netfilter/nf_tables_api.c:12136

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x133/0x180 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xe66/0x1180 kernel/hung_task.c:515
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 18617 Comm: syz.1.3091 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__sanitizer_cov_trace_switch+0x4b/0x90 kernel/kcov.c:350
Code: 08 74 5b 48 83 f8 10 75 2f 41 bd 03 00 00 00 4c 8b 75 00 31 db 4d 85 f6 74 1e 48 8b 74 dd 10 48 8b 4c 24 28 4c 89 e2 4c 89 ef <48> 83 c3 01 e8 8c fd ff ff 49 39 de 75 e2 5b 5d 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000c4cef10 EFLAGS: 00000202
RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff81c177a7
RDX: 0000000000000004 RSI: 000000000000001c RDI: 0000000000000001
RBP: ffffffff8b937200 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000004 R11: ffff8880314a2ff0 R12: 0000000000000004
R13: 0000000000000001 R14: 0000000000000005 R15: ffff88813ff66d94
FS:  00007ff3def976c0(0000) GS:ffff8881248f4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff3def96f98 CR3: 0000000034be9000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 rb_read_data_buffer.constprop.0+0x107/0x430 kernel/trace/ring_buffer.c:1862
 check_buffer+0x282/0x980 kernel/trace/ring_buffer.c:4412
 __rb_reserve_next.constprop.0+0x486/0x16d0 kernel/trace/ring_buffer.c:4511
 rb_reserve_next_event kernel/trace/ring_buffer.c:4648 [inline]
 ring_buffer_lock_reserve+0x459/0x11b0 kernel/trace/ring_buffer.c:4707
 __trace_buffer_lock_reserve kernel/trace/trace.c:1079 [inline]
 trace_event_buffer_lock_reserve+0x123/0x740 kernel/trace/trace.c:2808
 trace_event_buffer_reserve+0x1f7/0x350 kernel/trace/trace_events.c:672
 do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
 trace_event_raw_event_bpf_trace_printk+0x104/0x260 kernel/trace/bpf_trace.h:11
 __do_trace_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
 trace_bpf_trace_printk+0x11c/0x1b0 kernel/trace/bpf_trace.h:11
 ____bpf_trace_printk kernel/trace/bpf_trace.c:379 [inline]
 bpf_trace_printk+0x117/0x190 kernel/trace/bpf_trace.c:362
 bpf_prog_b1367f0be6c54012+0x39/0x3f
 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x239/0x5c0 kernel/trace/bpf_trace.c:2116
 __bpf_trace_contention_begin+0xc9/0x110 include/trace/events/lock.h:95
 __do_trace_contention_begin include/trace/events/lock.h:95 [inline]
 trace_contention_begin+0xc1/0x110 include/trace/events/lock.h:95
 __mutex_lock_common kernel/locking/mutex.c:616 [inline]
 __mutex_lock+0x1b7/0x1ca0 kernel/locking/mutex.c:776
 __unix_dgram_recvmsg+0x255/0xc30 net/unix/af_unix.c:2573
 unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2675
 sock_recvmsg_nosec net/socket.c:1078 [inline]
 ____sys_recvmsg+0x5f9/0x6b0 net/socket.c:2810
 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2854
 do_recvmmsg+0x2fe/0x750 net/socket.c:2949
 __sys_recvmmsg net/socket.c:3023 [inline]
 __do_sys_recvmmsg net/socket.c:3046 [inline]
 __se_sys_recvmmsg net/socket.c:3039 [inline]
 __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3039
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff3de18f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff3def97038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007ff3de3e6090 RCX: 00007ff3de18f749
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000008
RBP: 00007ff3de213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff3de3e6128 R14: 00007ff3de3e6090 R15: 00007ffddb8c73a8
 </TASK>