syzbot

INFO: task kworker/u4:17:6407 blocked for more than 145 seconds.
      Not tainted 6.1.0-syzkaller-13872-gb6bb9676f216 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:17   state:D stack:23192 pid:6407  ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x9d1/0xe40 kernel/sched/core.c:6555
 schedule+0xcb/0x190 kernel/sched/core.c:6631
 rxrpc_destroy_all_calls+0x585/0x680 net/rxrpc/call_object.c:733
 rxrpc_exit_net+0x6a/0xc0 net/rxrpc/net_ns.c:125
 ops_exit_list net/core/net_namespace.c:169 [inline]
 cleanup_net+0x758/0xc60 net/core/net_namespace.c:606
 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
 kthread+0x266/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d523910 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x30/0xd00 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d524110 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x30/0xd00 kernel/rcu/tasks.h:507
1 lock held by khungtaskd/28:
 #0: ffffffff8d523740 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/4746:
 #0: ffff888028a59098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc900015b02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6e8/0x1e50 drivers/tty/n_tty.c:2177
1 lock held by syz-executor.5/5097:
 #0: ffffffff8d528d78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #0: ffffffff8d528d78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a6/0x890 kernel/rcu/tree_exp.h:946
1 lock held by syz-executor.2/5106:
 #0: ffffffff8d528d78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
 #0: ffffffff8d528d78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x46f/0x890 kernel/rcu/tree_exp.h:946
3 locks held by kworker/u4:17/6407:
 #0: ffff8880129db138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x796/0xd10 kernel/workqueue.c:2262
 #1: ffffc90004e0fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7d0/0xd10 kernel/workqueue.c:2264
 #2: ffffffff8e657d10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf0/0xc60 net/core/net_namespace.c:568
2 locks held by kworker/0:10/7657:
3 locks held by kworker/u4:35/9430:
4 locks held by syz-executor.1/13188:
2 locks held by kworker/1:1/19485:
 #0: ffff888012872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x796/0xd10 kernel/workqueue.c:2262
 #1: ffffc9000577fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0xd10 kernel/workqueue.c:2264
3 locks held by syz-executor.0/20904:
2 locks held by syz-executor.0/20911:
3 locks held by syz-executor.3/20917:
1 lock held by syz-executor.3/20918:

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.0-syzkaller-13872-gb6bb9676f216 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e3/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x19b/0x3e0 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+0xcd5/0xd20 kernel/hung_task.c:377
 kthread+0x266/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 20923 Comm: syz-executor.4 Not tainted 6.1.0-syzkaller-13872-gb6bb9676f216 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0033:0x7f58bce39219
Code: 08 48 39 ca 77 f3 48 39 c3 73 3e 48 89 13 48 8b 50 f8 48 89 38 49 8b 0e 48 8b 3e 48 83 c3 08 48 83 c6 08 eb bc 48 39 d1 72 9e <48> 39 d0 73 47 49 89 16 48 89 fa 49 89 78 f8 49 8b 0e 49 8b 7e 08
RSP: 002b:00007ffd06b713e0 EFLAGS: 00000206
RAX: ffffffff81fb1da5 RBX: 00007f58bc400e98 RCX: ffffffff81fb1dda
RDX: ffffffff81fb1da5 RSI: 00007f58bc400e00 RDI: ffffffff81fc3fbd
RBP: 00007f58bc400d80 R08: 00007f58bc400e98 R09: 0000000036de1c65
R10: 00007ffd06b716a0 R11: 0000000000000246 R12: 00007f58bc400d78
R13: 00007f58bc400e98 R14: 00007f58bc400d70 R15: 000000000000000b
FS:  000055555695e400 GS:  0000000000000000