INFO: task kworker/u4:5:277 blocked for more than 143 seconds. Not tainted 5.7.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:5 D25784 277 2 0x80004000 Workqueue: netns cleanup_net Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4158 rwsem_down_write_slowpath+0x706/0xf90 kernel/locking/rwsem.c:1235 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x137/0x150 kernel/locking/rwsem.c:1532 unregister_shrinker+0x9b/0x2c0 mm/vmscan.c:403 nfsd_reply_cache_shutdown+0x22/0x350 fs/nfsd/nfscache.c:197 nfsd_exit_net+0x189/0x4c0 fs/nfsd/nfsctl.c:1504 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:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 4 locks held by kworker/u4:5/277: #0: ffff8880a9771938 ((wq_completion)netns){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a9771938 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a9771938 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a9771938 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a9771938 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880a9771938 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880a9771938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2239 #1: ffffc90001817dc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2243 #2: ffffffff8a576af0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa50 net/core/net_namespace.c:565 #3: ffffffff89a404f0 (shrinker_rwsem){++++}-{3:3}, at: unregister_shrinker+0x9b/0x2c0 mm/vmscan.c:403 1 lock held by khungtaskd/1133: #0: ffffffff899beb00 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754 2 locks held by khugepaged/1149: 1 lock held by in:imklog/6771: #0: ffff88809f1b3670 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by kworker/u4:7/9027: 4 locks held by kworker/u4:9/10718: 2 locks held by syz-executor.2/24760: #0: ffff88804b3760e0 (&type->s_umount_key#40){++++}-{3:3}, at: deactivate_super fs/super.c:365 [inline] #0: ffff88804b3760e0 (&type->s_umount_key#40){++++}-{3:3}, at: deactivate_super+0x185/0x1b0 fs/super.c:362 #1: ffffffff89a404f0 (shrinker_rwsem){++++}-{3:3}, at: unregister_memcg_shrinker.isra.0+0x26/0x50 mm/vmscan.c:236 3 locks held by kworker/0:2/3347: #0: ffff88809ac3f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff88809ac3f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88809ac3f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff88809ac3f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff88809ac3f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff88809ac3f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff88809ac3f538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2239 #1: ffffc90003e67dc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2243 #2: ffffffff8a5829e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xa9/0x1280 net/ipv6/addrconf.c:4043 1 lock held by syz-executor.5/5103: #0: ffffffff8a5829e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8a5829e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5451 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1133 Comm: khungtaskd Not tainted 5.7.0-rc4-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: 10718 Comm: kworker/u4:9 Not tainted 5.7.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: krdsd rds_connect_worker RIP: 0010:__lock_acquire+0x250d/0x4c50 kernel/locking/lockdep.c:4351 Code: ff 41 be 01 00 00 00 e9 18 e6 ff ff 48 8d 7d d8 e8 18 2d ff ff 48 ba 00 00 00 00 00 fc ff df 48 8d 78 40 48 89 f9 48 c1 e9 03 <80> 3c 11 00 0f 85 2e 1d 00 00 48 83 78 40 00 0f 85 4b e7 ff ff 0f RSP: 0018:ffffc90016a6f780 EFLAGS: 00000806 RAX: ffffffff8c3170b0 RBX: 00000000661ad43e RCX: 1ffffffff1862e1e RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffffff8c3170f0 RBP: ffff888047f1cf68 R08: 0000000000000001 R09: fffffbfff185cf4d R10: ffffffff8c2e7a67 R11: fffffbfff185cf4c R12: ffff888047f1c600 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff8a898210 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe2c268fdb8 CR3: 0000000051388000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4934 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:358 [inline] inet_csk_find_open_port net/ipv4/inet_connection_sock.c:224 [inline] inet_csk_get_port+0xc3c/0x2590 net/ipv4/inet_connection_sock.c:312 __inet_bind+0x5b2/0xbd0 net/ipv4/af_inet.c:524 inet_bind+0xf3/0x160 net/ipv4/af_inet.c:453 rds_tcp_conn_path_connect+0x536/0x880 net/rds/tcp_connect.c:144 rds_connect_worker+0x1a5/0x2c0 net/rds/threads.c:176 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352