====================================================== WARNING: possible circular locking dependency detected 4.17.0-rc2+ #22 Not tainted ------------------------------------------------------ syz-executor1/6653 is trying to acquire lock: (ptrval) (sk_lock-AF_INET6){+.+.}, at: lock_sock include/net/sock.h:1469 [inline] (ptrval) (sk_lock-AF_INET6){+.+.}, at: tcp_mmap+0x1c7/0x14f0 net/ipv4/tcp.c:1759 but task is already holding lock: (ptrval) (&mm->mmap_sem){++++}, at: vm_mmap_pgoff+0x1a1/0x2a0 mm/util.c:355 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_sem){++++}: __might_fault+0x155/0x1e0 mm/memory.c:4555 sctp_getsockopt_initmsg net/sctp/socket.c:5603 [inline] sctp_getsockopt+0x22a6/0x7b4b net/sctp/socket.c:7241 sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:3001 __sys_getsockopt+0x1a5/0x370 net/socket.c:1940 __do_sys_getsockopt net/socket.c:1951 [inline] __se_sys_getsockopt net/socket.c:1948 [inline] __x64_sys_getsockopt+0xbe/0x150 net/socket.c:1948 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (sk_lock-AF_INET6){+.+.}: lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920 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 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(sk_lock-AF_INET6); lock(&mm->mmap_sem); lock(sk_lock-AF_INET6); *** DEADLOCK *** 1 lock held by syz-executor1/6653: #0: (ptrval) (&mm->mmap_sem){++++}, at: vm_mmap_pgoff+0x1a1/0x2a0 mm/util.c:355 stack backtrace: CPU: 1 PID: 6653 Comm: syz-executor1 Not tainted 4.17.0-rc2+ #22 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 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 RIP: 0033:0x455979 RSP: 002b:00007f872091ec68 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f872091f6d4 RCX: 0000000000455979 RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffc000 RBP: 000000000072bea0 R08: 0000000000000013 R09: 0000000000000000 R10: 0000000000002811 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003fe R14: 00000000006f9070 R15: 0000000000000000 netlink: 20 bytes leftover after parsing attributes in process `syz-executor3'. netlink: 20 bytes leftover after parsing attributes in process `syz-executor3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'. IPVS: length: 120 != 24 IPVS: length: 120 != 24 netlink: 'syz-executor7': attribute type 29 has an invalid length. netlink: 'syz-executor7': attribute type 29 has an invalid length. syz-executor6 uses obsolete (PF_INET,SOCK_PACKET) kernel msg: ebtables bug: please report to author: Wrong len argument kernel msg: ebtables bug: please report to author: Hook order must be followed kernel msg: ebtables bug: please report to author: Hook order must be followed kernel msg: ebtables bug: please report to author: Wrong len argument netlink: 'syz-executor2': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 'syz-executor2': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 'syz-executor2': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 'syz-executor2': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 'syz-executor2': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 'syz-executor2': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 'syz-executor2': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 'syz-executor2': attribute type 29 has an invalid length. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'. FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 1 PID: 7800 Comm: syz-executor1 Not tainted 4.17.0-rc2+ #22 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 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0xa/0x1a lib/fault-inject.c:149 __should_failslab+0x124/0x180 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1522 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc_node mm/slab.c:3299 [inline] kmem_cache_alloc_node+0x272/0x780 mm/slab.c:3642 __alloc_skb+0x111/0x780 net/core/skbuff.c:193 alloc_skb include/linux/skbuff.h:989 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline] netlink_sendmsg+0xb01/0xfa0 net/netlink/af_netlink.c:1876 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 ___sys_sendmsg+0x805/0x940 net/socket.c:2117 __sys_sendmsg+0x115/0x270 net/socket.c:2155 __do_sys_sendmsg net/socket.c:2164 [inline] __se_sys_sendmsg net/socket.c:2162 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2162 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287