====================================================== WARNING: possible circular locking dependency detected 4.13.0-rc6-next-20170825+ #9 Not tainted ------------------------------------------------------ syz-executor2/3296 is trying to acquire lock: (cpu_hotplug_lock.rw_sem){++++}, at: [] get_online_cpus include/linux/cpu.h:126 [inline] (cpu_hotplug_lock.rw_sem){++++}, at: [] flush_all_backlogs net/core/dev.c:4592 [inline] (cpu_hotplug_lock.rw_sem){++++}, at: [] rollback_registered_many+0x587/0xe80 net/core/dev.c:7127 but task is already holding lock: (rtnl_mutex){+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (rtnl_mutex){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 addrconf_dad_work+0xbb/0xfc0 net/ipv6/addrconf.c:3890 process_one_work+0xbfd/0x1be0 kernel/workqueue.c:2098 worker_thread+0x223/0x1860 kernel/workqueue.c:2233 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 -> #3 ((&(&ifa->dad_work)->work)){+.+.}: process_one_work+0xba5/0x1be0 kernel/workqueue.c:2095 worker_thread+0x223/0x1860 kernel/workqueue.c:2233 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 0xffffffffffffffff -> #2 ((complete)wq_barr::done/1){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 complete_acquire include/linux/completion.h:39 [inline] __wait_for_common kernel/sched/completion.c:108 [inline] wait_for_common kernel/sched/completion.c:122 [inline] wait_for_completion+0xc8/0x770 kernel/sched/completion.c:143 flush_work+0x621/0x930 kernel/workqueue.c:2868 lru_add_drain_all_cpuslocked+0x331/0x520 mm/swap.c:722 lru_add_drain_all+0x13/0x20 mm/swap.c:730 SYSC_mlockall mm/mlock.c:803 [inline] SyS_mlockall+0x2fb/0x670 mm/mlock.c:791 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #1 (lock#4){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lru_add_drain_all_cpuslocked+0xb3/0x520 mm/swap.c:704 lru_add_drain_all+0x13/0x20 mm/swap.c:730 SYSC_mlockall mm/mlock.c:803 [inline] SyS_mlockall+0x2fb/0x670 mm/mlock.c:791 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #0 (cpu_hotplug_lock.rw_sem){++++}: check_prev_add+0x865/0x1520 kernel/locking/lockdep.c:1894 check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:35 [inline] percpu_down_read include/linux/percpu-rwsem.h:58 [inline] cpus_read_lock+0x42/0x90 kernel/cpu.c:218 get_online_cpus include/linux/cpu.h:126 [inline] flush_all_backlogs net/core/dev.c:4592 [inline] rollback_registered_many+0x587/0xe80 net/core/dev.c:7127 rollback_registered+0x1be/0x3c0 net/core/dev.c:7183 unregister_netdevice_queue+0x2e3/0x5d0 net/core/dev.c:8171 unregister_netdevice include/linux/netdevice.h:2428 [inline] __tun_detach+0x1020/0x1390 drivers/net/tun.c:576 tun_detach drivers/net/tun.c:587 [inline] tun_chr_close+0x44/0x60 drivers/net/tun.c:2595 __fput+0x333/0x7f0 fs/file_table.c:210 ____fput+0x15/0x20 fs/file_table.c:246 task_work_run+0x199/0x270 kernel/task_work.c:112 exit_task_work include/linux/task_work.h:21 [inline] do_exit+0xa52/0x1b40 kernel/exit.c:865 do_group_exit+0x149/0x400 kernel/exit.c:968 get_signal+0x7e8/0x17e0 kernel/signal.c:2334 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:808 exit_to_usermode_loop+0x224/0x300 arch/x86/entry/common.c:158 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath+0x42f/0x500 arch/x86/entry/common.c:266 entry_SYSCALL_64_fastpath+0xbc/0xbe other info that might help us debug this: Chain exists of: cpu_hotplug_lock.rw_sem --> (&(&ifa->dad_work)->work) --> rtnl_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock((&(&ifa->dad_work)->work)); lock(rtnl_mutex); lock(cpu_hotplug_lock.rw_sem); *** DEADLOCK *** 1 lock held by syz-executor2/3296: #0: (rtnl_mutex){+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 stack backtrace: CPU: 0 PID: 3296 Comm: syz-executor2 Not tainted 4.13.0-rc6-next-20170825+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 print_circular_bug+0x503/0x710 kernel/locking/lockdep.c:1259 check_prev_add+0x865/0x1520 kernel/locking/lockdep.c:1894 check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:35 [inline] percpu_down_read include/linux/percpu-rwsem.h:58 [inline] cpus_read_lock+0x42/0x90 kernel/cpu.c:218 get_online_cpus include/linux/cpu.h:126 [inline] flush_all_backlogs net/core/dev.c:4592 [inline] rollback_registered_many+0x587/0xe80 net/core/dev.c:7127 rollback_registered+0x1be/0x3c0 net/core/dev.c:7183 unregister_netdevice_queue+0x2e3/0x5d0 net/core/dev.c:8171 unregister_netdevice include/linux/netdevice.h:2428 [inline] __tun_detach+0x1020/0x1390 drivers/net/tun.c:576 tun_detach drivers/net/tun.c:587 [inline] tun_chr_close+0x44/0x60 drivers/net/tun.c:2595 __fput+0x333/0x7f0 fs/file_table.c:210 ____fput+0x15/0x20 fs/file_table.c:246 task_work_run+0x199/0x270 kernel/task_work.c:112 exit_task_work include/linux/task_work.h:21 [inline] do_exit+0xa52/0x1b40 kernel/exit.c:865 do_group_exit+0x149/0x400 kernel/exit.c:968 get_signal+0x7e8/0x17e0 kernel/signal.c:2334 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:808 exit_to_usermode_loop+0x224/0x300 arch/x86/entry/common.c:158 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath+0x42f/0x500 arch/x86/entry/common.c:266 entry_SYSCALL_64_fastpath+0xbc/0xbe RIP: 0033:0x4512e9 RSP: 002b:00007f425617acf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00000000007180c8 RCX: 00000000004512e9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000007180c8 RBP: 00000000007180a8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000a6f7ef R14: 00007f425617b9c0 R15: 0000000000000004 ICMPv6: NA: someone advertises our address fe80:0000:0000:0000:0000:0000:0000:04aa on syz4! ICMPv6: NA: someone advertises our address fe80:0000:0000:0000:0000:0000:0000:04aa on syz4! syz-executor2 uses obsolete (PF_INET,SOCK_PACKET) netlink: 3 bytes leftover after parsing attributes in process `syz-executor6'. netlink: 1 bytes leftover after parsing attributes in process `syz-executor6'. netlink: 3 bytes leftover after parsing attributes in process `syz-executor6'. netlink: 1 bytes leftover after parsing attributes in process `syz-executor6'. audit: type=1326 audit(1503755579.998:5): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=3443 comm="syz-executor2" exe="/root/syz-executor2" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4512e9 code=0xffff0000 audit: type=1326 audit(1503755580.080:6): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=3443 comm="syz-executor2" exe="/root/syz-executor2" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4512e9 code=0xffff0000 QAT: Invalid ioctl netlink: 3 bytes leftover after parsing attributes in process `syz-executor2'. QAT: Invalid ioctl SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=3632 comm=syz-executor4 capability: warning: `syz-executor3' uses 32-bit capabilities (legacy support in use) TCP: request_sock_TCPv6: Possible SYN flooding on port 20025. Sending cookies. Check SNMP counters. netlink: 1 bytes leftover after parsing attributes in process `syz-executor6'. IPv6: Can't replace route, no match found netlink: 1 bytes leftover after parsing attributes in process `syz-executor6'. IPv6: Can't replace route, no match found TCP: tcp_parse_options: Illegal window scaling value 243 > 14 received TCP: tcp_parse_options: Illegal window scaling value 243 > 14 received SELinux: unrecognized netlink message: protocol=0 nlmsg_type=6 sclass=netlink_route_socket pig=3963 comm=syz-executor0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=6 sclass=netlink_route_socket pig=3971 comm=syz-executor0 capability: warning: `syz-executor2' uses deprecated v2 capabilities in a way that may be insecure sctp: [Deprecated]: syz-executor1 (pid 4170) Use of int in maxseg socket option. Use struct sctp_assoc_value instead sctp: [Deprecated]: syz-executor1 (pid 4160) Use of int in maxseg socket option. Use struct sctp_assoc_value instead netlink: 8 bytes leftover after parsing attributes in process `syz-executor1'. netlink: 13 bytes leftover after parsing attributes in process `syz-executor6'. SELinux: unrecognized netlink message: protocol=6 nlmsg_type=0 sclass=netlink_xfrm_socket pig=4247 comm=syz-executor1 netlink: 13 bytes leftover after parsing attributes in process `syz-executor6'. audit: type=1326 audit(1503755584.604:7): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=4266 comm="syz-executor3" exe="/root/syz-executor3" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4512e9 code=0xffff0000 audit: type=1326 audit(1503755584.722:8): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=4266 comm="syz-executor3" exe="/root/syz-executor3" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4512e9 code=0xffff0000 TCP: request_sock_TCPv6: Possible SYN flooding on port 20021. Sending cookies. Check SNMP counters. RDS: rds_bind could not find a transport for 255.255.255.255, load rds_tcp or rds_rdma? QAT: Invalid ioctl RDS: rds_bind could not find a transport for 255.255.255.255, load rds_tcp or rds_rdma? audit: type=1326 audit(1503755584.878:9): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=4340 comm="syz-executor7" exe="/root/syz-executor7" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4512e9 code=0xffff0000 QAT: Invalid ioctl audit: type=1326 audit(1503755584.947:10): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=4340 comm="syz-executor7" exe="/root/syz-executor7" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4512e9 code=0xffff0000 netlink: 3 bytes leftover after parsing attributes in process `syz-executor5'. netlink: 3 bytes leftover after parsing attributes in process `syz-executor5'. QAT: Invalid ioctl mmap: syz-executor7 (4676) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.txt. netlink: 19 bytes leftover after parsing attributes in process `syz-executor1'. netlink: 13 bytes leftover after parsing attributes in process `syz-executor4'. netlink: 13 bytes leftover after parsing attributes in process `syz-executor4'. netlink: 3 bytes leftover after parsing attributes in process `syz-executor7'. netlink: 19 bytes leftover after parsing attributes in process `syz-executor1'. QAT: Invalid ioctl netlink: 3 bytes leftover after parsing attributes in process `syz-executor7'. netlink: 13 bytes leftover after parsing attributes in process `syz-executor6'. RDS: rds_bind could not find a transport for 224.0.0.1, load rds_tcp or rds_rdma? netlink: 1 bytes leftover after parsing attributes in process `syz-executor1'. device lo entered promiscuous mode device lo entered promiscuous mode TCP: request_sock_TCP: Possible SYN flooding on port 20023. Sending cookies. Check SNMP counters. device lo left promiscuous mode sock: process `syz-executor1' is using obsolete setsockopt SO_BSDCOMPAT SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4788 comm=syz-executor0 QAT: Invalid ioctl QAT: Invalid ioctl TCP: request_sock_TCP: Possible SYN flooding on port 20016. Sending cookies. Check SNMP counters. rpcbind: RPC call returned error 22 rpcbind: RPC call returned error 22 sctp: [Deprecated]: syz-executor6 (pid 5049) Use of int in max_burst socket option deprecated. Use struct sctp_assoc_value instead sctp: [Deprecated]: syz-executor6 (pid 5057) Use of int in max_burst socket option deprecated. Use struct sctp_assoc_value instead raw_sendmsg: syz-executor3 forgot to set AF_INET. Fix it! QAT: Invalid ioctl QAT: Invalid ioctl