INFO: task syz-executor.3:13560 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.3 D27736 13560 8287 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: 0033:0x7ff9c9ce6639 Code: Bad RIP value. RSP: 002b:00007ff9c8238168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007ff9c9e07050 RCX: 00007ff9c9ce6639 RDX: 0000000020000100 RSI: 0000000020000080 RDI: 0000000000000000 RBP: 00007ff9c9d41ae9 R08: 00000000200019c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe3eb8088f R14: 00007ff9c8238300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1569: #0: 00000000c097a18e (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 3 locks held by kworker/u4:3/2885: #0: 0000000077f11329 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000bf43f5cb (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000adf11f04 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521 1 lock held by systemd-journal/4695: #0: 00000000dba1da46 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1826 [inline] #0: 00000000dba1da46 (&rq->lock){-.-.}, at: __schedule+0x1f9/0x2040 kernel/sched/core.c:3455 2 locks held by kworker/1:3/8347: #0: 0000000041daee00 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 0000000078f5c897 ((work_completion)(&m->wq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 2 locks held by syz-executor.1/19828: #0: 00000000adf11f04 (pernet_ops_rwsem){++++}, at: copy_net_ns+0x1d8/0x340 net/core/net_namespace.c:435 #1: 000000002b82f02c (rcu_preempt_state.barrier_mutex){+.+.}, at: _rcu_barrier+0x59/0x3e0 kernel/rcu/tree.c:3430 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1569 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 9690 Comm: kworker/u4:8 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: phy6 ieee80211_iface_work RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:784 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:806 [inline] RIP: 0010:__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] RIP: 0010:_raw_spin_lock_irqsave+0x29/0xc0 kernel/locking/spinlock.c:152 Code: 00 48 c7 c0 80 82 f1 89 41 54 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 55 48 89 fd 80 3c 10 00 75 7f 48 83 3d 47 35 d8 01 00 <74> 71 9c 58 0f 1f 44 00 00 48 ba 00 00 00 00 00 fc ff df 49 89 c4 RSP: 0018:ffff888040dc7bb8 EFLAGS: 00000086 RAX: 1ffffffff13e3050 RBX: 0000000000000000 RCX: ffffffff8d40f308 RDX: dffffc0000000000 RSI: ffff8880a13f3000 RDI: ffffffff8d40f308 RBP: ffffffff8d40f308 R08: 0000000000400000 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000286 R13: ffff8880a13f3a80 R14: ffffffff879b7389 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f59b2be8000 CR3: 0000000095f16000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __debug_check_no_obj_freed lib/debugobjects.c:776 [inline] debug_check_no_obj_freed+0xb5/0x490 lib/debugobjects.c:817 kmem_cache_free+0xff/0x260 mm/slab.c:3764 kfree_skbmem+0xc1/0x140 net/core/skbuff.c:595 __kfree_skb net/core/skbuff.c:655 [inline] kfree_skb+0x127/0x3d0 net/core/skbuff.c:672 ieee80211_iface_work+0x289/0x8a0 net/mac80211/iface.c:1353 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