====================================================== WARNING: possible circular locking dependency detected 4.17.0-rc2+ #24 Not tainted ------------------------------------------------------ syz-executor4/6642 is trying to acquire lock: (ptrval) (&mm->mmap_sem){++++}, at: __might_fault+0xfb/0x1e0 mm/memory.c:4554 but task is already holding lock: (ptrval) (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1469 [inline] (ptrval) (sk_lock-AF_INET6){+.+.}, at: do_ipv6_setsockopt.isra.9+0x5ba/0x4680 net/ipv6/ipv6_sockglue.c:167 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (sk_lock-AF_INET6){+.+.}: lock_sock_nested+0xd0/0x120 net/core/sock.c:2844 lock_sock include/net/sock.h:1469 [inline] tcp_mmap+0x1c7/0x14f0 net/ipv4/tcp.c:1759 sock_mmap+0x8e/0xc0 net/socket.c:1144 call_mmap include/linux/fs.h:1789 [inline] mmap_region+0xd13/0x1820 mm/mmap.c:1723 do_mmap+0xc79/0x11d0 mm/mmap.c:1494 do_mmap_pgoff include/linux/mm.h:2237 [inline] vm_mmap_pgoff+0x1fb/0x2a0 mm/util.c:357 ksys_mmap_pgoff+0x4c9/0x640 mm/mmap.c:1544 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&mm->mmap_sem){++++}: lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920 __might_fault+0x155/0x1e0 mm/memory.c:4555 _copy_from_user+0x30/0x150 lib/usercopy.c:10 copy_from_user include/linux/uaccess.h:147 [inline] memdup_user+0x54/0xa0 mm/util.c:164 xfrm_user_policy+0x1c0/0xae0 net/xfrm/xfrm_state.c:2074 do_ipv6_setsockopt.isra.9+0x881/0x4680 net/ipv6/ipv6_sockglue.c:810 ipv6_setsockopt+0xbd/0x170 net/ipv6/ipv6_sockglue.c:922 udpv6_setsockopt+0x62/0xa0 net/ipv6/udp.c:1445 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3042 __sys_setsockopt+0x1bd/0x390 net/socket.c:1903 __do_sys_setsockopt net/socket.c:1914 [inline] __se_sys_setsockopt net/socket.c:1911 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sk_lock-AF_INET6); lock(&mm->mmap_sem); lock(sk_lock-AF_INET6); lock(&mm->mmap_sem); *** DEADLOCK *** 1 lock held by syz-executor4/6642: #0: (ptrval) (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1469 [inline] #0: (ptrval) (sk_lock-AF_INET6){+.+.}, at: do_ipv6_setsockopt.isra.9+0x5ba/0x4680 net/ipv6/ipv6_sockglue.c:167 stack backtrace: CPU: 1 PID: 6642 Comm: syz-executor4 Not tainted 4.17.0-rc2+ #24 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+0x1b9/0x294 lib/dump_stack.c:113 print_circular_bug.isra.36.cold.54+0x1bd/0x27d kernel/locking/lockdep.c:1223 check_prev_add kernel/locking/lockdep.c:1863 [inline] check_prevs_add kernel/locking/lockdep.c:1976 [inline] validate_chain kernel/locking/lockdep.c:2417 [inline] __lock_acquire+0x343e/0x5140 kernel/locking/lockdep.c:3431 lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920 __might_fault+0x155/0x1e0 mm/memory.c:4555 _copy_from_user+0x30/0x150 lib/usercopy.c:10 copy_from_user include/linux/uaccess.h:147 [inline] memdup_user+0x54/0xa0 mm/util.c:164 xfrm_user_policy+0x1c0/0xae0 net/xfrm/xfrm_state.c:2074 do_ipv6_setsockopt.isra.9+0x881/0x4680 net/ipv6/ipv6_sockglue.c:810 ipv6_setsockopt+0xbd/0x170 net/ipv6/ipv6_sockglue.c:922 udpv6_setsockopt+0x62/0xa0 net/ipv6/udp.c:1445 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3042 __sys_setsockopt+0x1bd/0x390 net/socket.c:1903 __do_sys_setsockopt net/socket.c:1914 [inline] __se_sys_setsockopt net/socket.c:1911 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455979 RSP: 002b:00007f4dc4630c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f4dc46316d4 RCX: 0000000000455979 RDX: 0000000000000023 RSI: 0000000000000029 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 00000000000000e8 R09: 0000000000000000 R10: 00000000200001c0 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000596 R14: 00000000006fc6b0 R15: 0000000000000000 netlink: 'syz-executor0': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'. netlink: 'syz-executor0': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'. netlink: 'syz-executor0': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'. netlink: 'syz-executor0': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'. netlink: 'syz-executor0': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'. netlink: 'syz-executor0': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'. IPVS: sync thread started: state = BACKUP, mcast_ifn = bridge_slave_0, syncid = 0, id = 0 IPVS: stopping backup sync thread 6708 ... IPVS: sync thread started: state = BACKUP, mcast_ifn = bridge_slave_0, syncid = 0, id = 0 IPVS: stopping backup sync thread 6725 ... xt_cluster: you have exceeded the maximum number of cluster nodes (4095 > 32) xt_cluster: you have exceeded the maximum number of cluster nodes (4095 > 32) IPVS: ftp: loaded support on port[0] = 21 kernel msg: ebtables bug: please report to author: Nentries wrong ebt_limit: overflow, try lower: 0/0 IPVS: ftp: loaded support on port[0] = 21 ebt_limit: overflow, try lower: 0/0 device bridge0 entered promiscuous mode kernel msg: ebtables bug: please report to author: Nentries wrong device bridge0 left promiscuous mode netlink: 'syz-executor7': attribute type 1 has an invalid length. netlink: 192 bytes leftover after parsing attributes in process `syz-executor5'. IPVS: ftp: loaded support on port[0] = 21 netlink: 'syz-executor7': attribute type 1 has an invalid length. netlink: 192 bytes leftover after parsing attributes in process `syz-executor5'. IPVS: ftp: loaded support on port[0] = 21 nla_parse: 4 callbacks suppressed netlink: 4 bytes leftover after parsing attributes in process `syz-executor4'. IPVS: set_ctl: invalid protocol: 127 224.0.0.1:20000 rr device lo entered promiscuous mode IPVS: set_ctl: invalid protocol: 127 224.0.0.1:20000 rr device lo left promiscuous mode IPVS: set_ctl: invalid protocol: 60 172.20.20.187:20000 lblcr IPVS: set_ctl: invalid protocol: 60 172.20.20.187:20000 lblcr IPVS: sync thread started: state = BACKUP, mcast_ifn = bridge0, syncid = 0, id = 0 IPVS: ftp: loaded support on port[0] = 21 netlink: 'syz-executor5': attribute type 2 has an invalid length. netlink: 'syz-executor5': attribute type 2 has an invalid length. netlink: 3 bytes leftover after parsing attributes in process `syz-executor0'. TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. netlink: 3 bytes leftover after parsing attributes in process `syz-executor0'.