syzbot

INFO: task syz.1.727:9705 blocked for more than 142 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.727       state:D stack:27272 pid:9705  tgid:9702  ppid:5829   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121
 __flush_workqueue+0x3f7/0x1200 kernel/workqueue.c:4084
 rxrpc_destroy_all_connections+0xf9/0x420 net/rxrpc/conn_object.c:477
 rxrpc_exit_net+0x7b/0xc0 net/rxrpc/net_ns.c:113
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x2ee/0xab0 net/core/net_namespace.c:252
 setup_net+0x1fa/0x3a0 net/core/net_namespace.c:462
 copy_net_ns+0x46f/0x7c0 net/core/net_namespace.c:579
 create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:130
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x473/0xad0 kernel/fork.c:3173
 __do_sys_unshare kernel/fork.c:3244 [inline]
 __se_sys_unshare kernel/fork.c:3242 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3242
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f57e299c819
RSP: 002b:00007f57e3792028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f57e2c16090 RCX: 00007f57e299c819
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000080
RBP: 00007f57e2a32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f57e2c16128 R14: 00007f57e2c16090 R15: 00007ffe33888f28
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/0:1/10:
 #0: ffff88813fe63148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
 #1: ffff8880543fc008 (&____s->seqcount#15){.-.-}-{0:0}, at: trace_find_filtered_pid kernel/trace/trace_pid.c:15 [inline]
 #1: ffff8880543fc008 (&____s->seqcount#15){.-.-}-{0:0}, at: trace_ignore_this_task+0xbc/0x100 kernel/trace/trace_pid.c:44
 #2: ffff8880b8426358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x124/0x1d0 kernel/time/timer.c:1004
 #3: ffffffff9b416238 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x144/0x490 lib/debugobjects.c:835
1 lock held by khungtaskd/32:
 #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by getty/9509:
 #0: ffff888033f3c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900026062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
1 lock held by syz.1.727/9705:
 #0: ffffffff905febd0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575
3 locks held by kworker/u10:4/9795:
 #0: ffff88801c6b6948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
 #1: ffffc90004d77d08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
 #2: ffffffff905febd0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673
1 lock held by syz.4.760/9870:
 #0: ffffffff905febd0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575
2 locks held by kworker/u10:8/10140:
 #0: ffff8880b843b360 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x140 kernel/sched/core.c:647
 #1: ffff8880543fc008 (&____s->seqcount#15){.-.-}-{0:0}, at: trace_find_filtered_pid kernel/trace/trace_pid.c:15 [inline]
 #1: ffff8880543fc008 (&____s->seqcount#15){.-.-}-{0:0}, at: trace_ignore_this_task+0xbc/0x100 kernel/trace/trace_pid.c:44
2 locks held by kworker/u10:9/10141:
 #0: ffff88801df65948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
 #1: ffffc900036b7d08 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
1 lock held by syz.5.924/10703:
 #0: ffffffff905febd0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575
1 lock held by syz.6.932/10740:
 #0: ffff8880598dc148 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff8880598dc148 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:661
1 lock held by syz.0.1193/11816:
 #0: ffff888089ceb008 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888089ceb008 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:661
1 lock held by syz.8.1219/11936:
1 lock held by syz.7.1225/11957:
 #0: ffffffff905febd0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:575
1 lock held by syz.8.1244/12016:
 #0: ffffffff8e7f32b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
3 locks held by syz.8.1244/12020:
 #0: ffff8880545011c0 (&tty->legacy_mutex){+.+.}-{4:4}, at: __tty_hangup.part.0+0xd9/0x7f0 drivers/tty/tty_io.c:581
 #1: ffff8880545010a0 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:289 [inline]
 #1: ffff8880545010a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock+0x65/0xb0 drivers/tty/tty_ldisc.c:313
 #2: ffffffff90617428 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff90617428 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2162

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xd25/0x1050 kernel/hung_task.c:515
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>