INFO: task kworker/u4:6:8840 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:6 D24352 8840 2 0x80000000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common+0x29c/0x470 kernel/sched/completion.c:115 IPVS: ftp: loaded support on port[0] = 21 flush_workqueue+0x40b/0x13e0 kernel/workqueue.c:2713 flush_scheduled_work include/linux/workqueue.h:599 [inline] tipc_exit_net+0x38/0x60 net/tipc/core.c:100 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:554 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 INFO: task syz-executor.0:25238 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D27272 25238 8120 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common+0x29c/0x470 kernel/sched/completion.c:115 __flush_work+0x4bb/0x8b0 kernel/workqueue.c:2926 __cancel_work_timer+0x412/0x590 kernel/workqueue.c:3013 p9_conn_destroy net/9p/trans_fd.c:904 [inline] p9_fd_close+0x305/0x520 net/9p/trans_fd.c:934 p9_client_create+0x901/0x12e0 net/9p/client.c:1084 v9fs_session_init+0x1dd/0x1770 fs/9p/v9fs.c:421 v9fs_mount+0x73/0x910 fs/9p/vfs_super.c:135 mount_fs+0xa3/0x310 fs/super.c:1261 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2492 [inline] do_mount+0x115c/0x2f50 fs/namespace.c:2822 ksys_mount+0xcf/0x130 fs/namespace.c:3038 __do_sys_mount fs/namespace.c:3052 [inline] __se_sys_mount fs/namespace.c:3049 [inline] __x64_sys_mount+0xba/0x150 fs/namespace.c:3049 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fb43cfb80d9 Code: Bad RIP value. RSP: 002b:00007fb43b509168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fb43d0d8050 RCX: 00007fb43cfb80d9 RDX: 0000000020000100 RSI: 0000000020000080 RDI: 0000000000000000 RBP: 00007fb43d013ae9 R08: 0000000020000180 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdb18d972f R14: 00007fb43b509300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1571: #0: 0000000095fa2503 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 2 locks held by kworker/0:2/3687: #0: 00000000aa6f92a0 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000f35428e8 ((work_completion)(&m->wq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 1 lock held by in:imklog/7798: #0: 00000000de4a310d (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 3 locks held by kworker/u4:6/8840: #0: 0000000080f0f7f1 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000378f3428 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000c0f23238 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521 2 locks held by syz-executor.1/1555: 2 locks held by syz-executor.2/1557: #0: 00000000c078e6ba (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1826 [inline] #0: 00000000c078e6ba (&rq->lock){-.-.}, at: __schedule+0x1f9/0x2040 kernel/sched/core.c:3455 #1: 0000000095fa2503 (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:428 [inline] #1: 0000000095fa2503 (rcu_read_lock){....}, at: update_curr+0x2c3/0x870 kernel/sched/fair.c:857 3 locks held by syz-executor.1/1589: 2 locks held by syz-executor.4/1593: 2 locks held by syz-executor.2/1595: #0: 00000000c078e6ba (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1826 [inline] #0: 00000000c078e6ba (&rq->lock){-.-.}, at: __schedule+0x1f9/0x2040 kernel/sched/core.c:3455 #1: 0000000095fa2503 (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:428 [inline] #1: 0000000095fa2503 (rcu_read_lock){....}, at: update_curr+0x2c3/0x870 kernel/sched/fair.c:857 3 locks held by syz-executor.5/1597: 3 locks held by syz-executor.0/1599: #0: 000000008ac35bc2 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1945 [inline] #0: 000000008ac35bc2 (tty_mutex){+.+.}, at: tty_open+0x387/0x990 drivers/tty/tty_io.c:2029 #1: 0000000013b70eab (&tty->legacy_mutex){+.+.}, at: tty_lock+0x6a/0xa0 drivers/tty/tty_mutex.c:19 #2: 0000000022a0f6db (console_lock){+.+.}, at: con_install+0x8b/0x590 drivers/tty/vt/vt.c:3256 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1571 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 1589 Comm: syz-executor.1 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:784 [inline] RIP: 0010:lockdep_hardirqs_on+0x126/0x5c0 kernel/locking/lockdep.c:2867 Code: 00 44 8b 0d fc df d8 0b 45 85 c9 0f 85 f2 00 00 00 48 c7 c0 80 82 f1 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 <0f> 85 48 04 00 00 48 83 3d ec 2a a6 08 00 0f 84 60 03 00 00 9c 58 RSP: 0000:ffff888041e77e18 EFLAGS: 00000046 RAX: 1ffffffff13e3050 RBX: ffffffff8d243760 RCX: 1ffffffff148be2c RDX: dffffc0000000000 RSI: ffffffff8167a995 RDI: ffff8880b2f60c90 RBP: ffffffff818cfd59 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000055 R13: 00007f1df9d41718 R14: 0000000000000015 R15: ffff88809bed4880 FS: 0000555556637400(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1df9d41718 CR3: 000000008fa5c000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 000000000000062a Call Trace: count_memcg_events include/linux/memcontrol.h:745 [inline] count_memcg_event_mm include/linux/memcontrol.h:766 [inline] handle_mm_fault+0x829/0xb10 mm/memory.c:4316 __do_page_fault+0x68e/0xd60 arch/x86/mm/fault.c:1412 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1205 RIP: 0033:0x7f1dfb77e8df Code: ff ff 4d 89 cd 48 85 c0 74 19 8b 95 44 ff ff ff 48 29 c6 48 01 c7 e8 10 09 05 00 85 c0 0f 85 0b 03 00 00 48 8b 85 48 ff ff ff <41> c7 45 18 01 00 00 00 4c 89 ef 49 89 85 90 06 00 00 48 8b 85 50 RSP: 002b:00007ffea3914920 EFLAGS: 00010246 RAX: 00007f1df9d21000 RBX: 0000000000021000 RCX: 00007f1dfb7cf1e7 RDX: 0000000000000003 RSI: 0000000000020000 RDI: 00007f1df9d22000 RBP: 00007ffea39149f0 R08: 00000000ffffffff R09: 00007f1df9d41700 R10: 0000000000020022 R11: 0000000000000206 R12: 00007ffea3914b10 R13: 00007f1df9d41700 R14: 0000000000000000 R15: 0000000000022000