XFS (loop3): Invalid superblock magic number XFS (loop3): Invalid superblock magic number INFO: task kworker/u4:7:9551 blocked for more than 140 seconds. Not tainted 4.19.158-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:7 D27672 9551 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 flush_workqueue+0x40b/0x13e0 kernel/workqueue.c:2715 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:553 process_one_work+0x864/0x1570 kernel/workqueue.c:2155 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Showing all locks held in the system: 1 lock held by khungtaskd/1566: #0: 00000000a5a7a6c2 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440 1 lock held by in:imklog/7791: #0: 00000000f652e939 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 2 locks held by syz-fuzzer/8106: 3 locks held by kworker/1:4/9362: #0: 000000000e49ec09 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2126 #1: 000000007c6d467a ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2130 #2: 0000000026ffd96f (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline] #2: 0000000026ffd96f (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314 3 locks held by kworker/u4:7/9551: #0: 000000003e54aa09 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2126 #1: 00000000f7504386 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2130 #2: 0000000060581b37 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:520 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1566 Comm: khungtaskd Not tainted 4.19.158-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2fe lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb 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: 8106 Comm: syz-fuzzer Not tainted 4.19.158-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_release kernel/locking/lockdep.c:3713 [inline] RIP: 0010:lock_release+0x3aa/0x8b0 kernel/locking/lockdep.c:3926 Code: 00 00 00 00 fc ff df 48 89 da 83 e3 07 48 c1 ea 03 83 c3 03 0f b6 04 02 38 c3 7c 08 84 c0 0f 85 d3 02 00 00 8b 15 66 ff d6 0b <85> d2 0f 84 67 01 00 00 65 48 8b 1c 25 80 df 01 00 48 8d bb 84 08 RSP: 0018:ffff888094b9fc78 EFLAGS: 00000097 RAX: 0000000000000004 RBX: 0000000000000003 RCX: 1ffff110162ad9b1 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8880b156c500 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff11012973f92 R13: 0000000000000000 R14: ffff8880b156c500 R15: 0000000000000001 FS: 000000c00003e410(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3f81d70000 CR3: 00000000aa3be000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: up_read+0x17/0x110 kernel/locking/rwsem.c:119 __do_sys_madvise mm/madvise.c:892 [inline] __se_sys_madvise+0x1272/0x1c10 mm/madvise.c:801 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x469067 Code: 8b 24 24 48 8b 6c 24 10 48 83 c4 18 c3 cc cc cc cc cc cc 48 8b 7c 24 08 48 8b 74 24 10 8b 54 24 18 48 c7 c0 1c 00 00 00 0f 05 <89> 44 24 20 c3 cc cc cc cc 48 8b 7c 24 08 8b 74 24 10 8b 54 24 14 RSP: 002b:000000c00004fe28 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 000000c019600000 RCX: 0000000000469067 RDX: 0000000000000008 RSI: 0000000000006000 RDI: 000000c0194be000 RBP: 000000c00004fe68 R08: 000000c0194c4000 R09: 0000000000000008 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000003300 R14: 00007f3f8b585000 R15: 0000000000000000