INFO: task kworker/u4:14:26510 blocked for more than 143 seconds. Not tainted 5.6.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:14 D24784 26510 2 0x80004000 Workqueue: netns cleanup_net Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4168 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4227 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 ip_set_net_exit+0x194/0x5b0 net/netfilter/ipset/ip_set_core.c:2401 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186 cleanup_net+0x511/0xa50 net/core/net_namespace.c:603 process_one_work+0x965/0x16a0 kernel/workqueue.c:2266 worker_thread+0x96/0xe20 kernel/workqueue.c:2412 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 INFO: task syz-executor.4:7803 blocked for more than 143 seconds. Not tainted 5.6.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28272 7803 7506 0x80004006 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4168 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4227 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 ip_set_net_exit+0x194/0x5b0 net/netfilter/ipset/ip_set_core.c:2401 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186 setup_net+0x50c/0x860 net/core/net_namespace.c:364 copy_net_ns+0x293/0x590 net/core/net_namespace.c:482 create_new_namespaces+0x3fb/0xb30 kernel/nsproxy.c:108 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:229 ksys_unshare+0x43d/0x8e0 kernel/fork.c:2955 __do_sys_unshare kernel/fork.c:3023 [inline] __se_sys_unshare kernel/fork.c:3021 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3021 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c849 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f2cde028c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f2cde0296d4 RCX: 000000000045c849 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000 RBP: 000000000076c0e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000c40 R14: 00000000004ce650 R15: 000000000076c0ec Showing all locks held in the system: 8 locks held by kworker/u4:4/137: 1 lock held by khungtaskd/1137: #0: ffffffff899bab40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5743 1 lock held by in:imklog/6763: #0: ffff8880974118b0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 4 locks held by kworker/u4:14/26510: #0: ffff88821b042138 ((wq_completion)netns){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff88821b042138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88821b042138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff88821b042138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff88821b042138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff88821b042138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff88821b042138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2237 #1: ffffc90005347dc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2241 #2: ffffffff8a55a9b0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa50 net/core/net_namespace.c:565 #3: ffffffff8d1c8a18 (&table[i].mutex){+.+.}-{3:3}, at: ip_set_net_exit+0x194/0x5b0 net/netfilter/ipset/ip_set_core.c:2401 2 locks held by syz-executor.3/7782: 2 locks held by syz-executor.4/7803: #0: ffffffff8a55a9b0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x270/0x590 net/core/net_namespace.c:478 #1: ffffffff8d1c8a18 (&table[i].mutex){+.+.}-{3:3}, at: ip_set_net_exit+0x194/0x5b0 net/netfilter/ipset/ip_set_core.c:2401 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1137 Comm: khungtaskd Not tainted 5.6.0-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7782 Comm: syz-executor.3 Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:debug_lockdep_rcu_enabled.part.0+0x14/0x50 kernel/rcu/update.c:276 Code: 48 89 ef e8 5e 85 50 00 e9 5a fe ff ff 66 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 53 65 48 8b 1c 25 00 1f 02 00 <48> 8d bb bc 08 00 00 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 RSP: 0018:ffffc90006446bc8 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: ffff88808b062240 RCX: 1ffffffff1510032 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8a87cf80 RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff150f9f1 R10: fffffbfff150f9f0 R11: ffffffff8a87cf87 R12: 0000000000000002 R13: ffffffff899bab40 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fc88d44a700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efc76c95010 CR3: 00000000551cb000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x3cd/0x8f0 kernel/locking/lockdep.c:4922 rcu_lock_acquire include/linux/rcupdate.h:208 [inline] rcu_read_lock include/linux/rcupdate.h:601 [inline] cond_resched_rcu include/linux/sched.h:1807 [inline] hash_ipportnet4_list+0x336/0x13a0 net/netfilter/ipset/ip_set_hash_gen.h:1369 ip_set_dump_do+0xca8/0x1970 net/netfilter/ipset/ip_set_core.c:1646 netlink_dump+0x50b/0xf50 net/netlink/af_netlink.c:2245 __netlink_dump_start+0x63f/0x910 net/netlink/af_netlink.c:2353 netlink_dump_start include/linux/netlink.h:246 [inline] ip_set_dump+0x133/0x1a0 net/netfilter/ipset/ip_set_core.c:1705 nfnetlink_rcv_msg+0xc83/0xf30 net/netfilter/nfnetlink.c:229 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2469 nfnetlink_rcv+0x1ac/0x420 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 sock_no_sendpage+0xf8/0x140 net/core/sock.c:2763 kernel_sendpage+0x82/0xd0 net/socket.c:3808 sock_sendpage+0x8a/0xb0 net/socket.c:950 pipe_to_sendpage+0x2aa/0x380 fs/splice.c:458 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x3e6/0x7b0 fs/splice.c:636 splice_from_pipe+0xd9/0x140 fs/splice.c:671 do_splice_from fs/splice.c:863 [inline] direct_splice_actor+0x115/0x160 fs/splice.c:1037 splice_direct_to_actor+0x38c/0x980 fs/splice.c:992 do_splice_direct+0x1b4/0x280 fs/splice.c:1080 do_sendfile+0x555/0xc50 fs/read_write.c:1520 __do_sys_sendfile64 fs/read_write.c:1581 [inline] __se_sys_sendfile64 fs/read_write.c:1567 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1567 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c849 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc88d449c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fc88d44a6d4 RCX: 000000000045c849 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000100000001 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008d4 R14: 00000000004cb786 R15: 000000000076bf0c