INFO: task kworker/u4:7:2453 blocked for more than 143 seconds. Not tainted 6.8.0-rc2-next-20240202-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:7 state:D stack:22896 pid:2453 tgid:2453 ppid:2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5400 [inline] __schedule+0x17df/0x4a40 kernel/sched/core.c:6727 __schedule_loop kernel/sched/core.c:6804 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6819 schedule_timeout+0xb0/0x310 kernel/time/timer.c:2159 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common kernel/sched/completion.c:116 [inline] wait_for_common kernel/sched/completion.c:127 [inline] wait_for_completion+0x355/0x620 kernel/sched/completion.c:148 __flush_workqueue+0x730/0x1630 kernel/workqueue.c:3617 rds_tcp_listen_stop+0x145/0x170 net/rds/tcp_listen.c:347 rds_tcp_kill_sock net/rds/tcp.c:614 [inline] rds_tcp_exit_net+0x139/0x660 net/rds/tcp.c:637 ops_exit_list net/core/net_namespace.c:170 [inline] cleanup_net+0x6da/0xb90 net/core/net_namespace.c:618 process_one_work kernel/workqueue.c:3049 [inline] process_scheduled_works+0x913/0x14f0 kernel/workqueue.c:3125 worker_thread+0xa60/0x1000 kernel/workqueue.c:3206 kthread+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614 3 locks held by kworker/u4:7/2453: #0: ffff888015acd948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3024 [inline] #0: ffff888015acd948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x14f0 kernel/workqueue.c:3125 #1: ffffc90009cf7d20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3024 [inline] #1: ffffc90009cf7d20 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x14f0 kernel/workqueue.c:3125 #2: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf5/0xb90 net/core/net_namespace.c:580 2 locks held by getty/4830: #0: ffff88802a4640a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002f162f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201 2 locks held by kworker/u4:10/6101: 1 lock held by syz-executor.0/7629: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 1 lock held by syz-executor.2/7822: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 1 lock held by syz-executor.3/7844: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 1 lock held by syz-executor.4/7861: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 1 lock held by syz-executor.1/7871: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 1 lock held by syz-executor.0/7882: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 1 lock held by syz-executor.3/7949: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 1 lock held by syz-executor.1/8055: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 1 lock held by syz-executor.0/8092: #0: ffffffff8f36da50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c8/0x7b0 net/core/net_namespace.c:491 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc2-next-20240202-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xfb0/0xff0 kernel/hung_task.c:379 kthread+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4735 Comm: dhcpcd Not tainted 6.8.0-rc2-next-20240202-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 RIP: 0010:__lock_acquire+0x46c/0x1fd0 Code: 24 5c 00 0f 95 c2 c1 e2 13 41 c1 e7 15 41 09 d7 41 09 c7 41 09 cf 41 09 ff 48 8b 44 24 20 0f b6 04 30 84 c0 0f 85 13 13 00 00 <44> 8b a4 24 e0 00 00 00 48 8b 44 24 10 44 89 38 49 89 c7 4c 8b 74 RSP: 0018:ffffc90002f6f550 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000028 RCX: 0000000000040000 RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 0000000000008028 RBP: 0000000000000000 R08: ffff888017b5e4d8 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1f0b6e6 R12: ffff8880b94425d8 R13: 0000000000000028 R14: 0000000000000001 R15: 0000000000048028 FS: 00007feec6e8d740(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005606080147a8 CR3: 00000000228de000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_trylock include/linux/spinlock_api_smp.h:90 [inline] _raw_spin_trylock+0x46/0x80 kernel/locking/spinlock.c:138 spin_trylock include/linux/spinlock.h:361 [inline] free_unref_page+0x15a/0x3f0 mm/page_alloc.c:2549 folio_put include/linux/mm.h:1494 [inline] free_large_kmalloc+0x105/0x1c0 mm/slub.c:4377 kfree+0x1c1/0x380 mm/slub.c:4400 skb_kfree_head net/core/skbuff.c:986 [inline] skb_free_head net/core/skbuff.c:998 [inline] skb_release_data+0x666/0x850 net/core/skbuff.c:1028 skb_release_all net/core/skbuff.c:1094 [inline] __kfree_skb net/core/skbuff.c:1108 [inline] consume_skb+0xb3/0x160 net/core/skbuff.c:1324 netlink_recvmsg+0x60a/0x11d0 net/netlink/af_netlink.c:1986 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg+0x22f/0x280 net/socket.c:1068 ____sys_recvmsg+0x1db/0x470 net/socket.c:2803 ___sys_recvmsg net/socket.c:2845 [inline] __sys_recvmsg+0x2f0/0x3e0 net/socket.c:2875 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7feec6f6591e Code: ff 89 ef 48 89 04 24 e8 4f 57 f9 ff 48 8b 04 24 48 83 c4 30 5d c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 21 b8 2f 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 70 48 8b 15 db c4 0c 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffd1e030008 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 000000000000000f RCX: 00007feec6f6591e RDX: 0000000000000000 RSI: 00007ffd1e030040 RDI: 000000000000000f RBP: 00007ffd1e038478 R08: 00005651d9dbf81d R09: 00007ffd1e0341a4 R10: 00007ffd1e0386c0 R11: 0000000000000246 R12: 00005651d9dbf81d R13: 0000000000000000 R14: 00007ffd1e038478 R15: 0000000002011eac