netlink: 'syz-executor0': attribute type 6 has an invalid length.

======================================================
WARNING: possible circular locking dependency detected
4.17.0-rc2+ #22 Not tainted
------------------------------------------------------
syz-executor4/7119 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
       _copy_from_user+0x30/0x150 lib/usercopy.c:10
       copy_from_user include/linux/uaccess.h:147 [inline]
       sctp_setsockopt_maxseg net/sctp/socket.c:3227 [inline]
       sctp_setsockopt+0x230d/0x7000 net/sctp/socket.c:4297
       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

-> #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-executor4/7119:
 #0:         (ptrval) (&mm->mmap_sem){++++}, at: vm_mmap_pgoff+0x1a1/0x2a0 mm/util.c:355

stack backtrace:
CPU: 1 PID: 7119 Comm: syz-executor4 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:00007f5ca1fbfc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f5ca1fc06d4 RCX: 0000000000455979
RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffc000
RBP: 000000000072bf50 R08: 0000000000000013 R09: 0000000000000000
R10: 0000000000002811 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000003fe R14: 00000000006f9070 R15: 0000000000000001
IPVS: Unknown mcast interface: bcsf0
kernel msg: ebtables bug: please report to author: nentries does not equal the nr of entries in the chain
kernel msg: ebtables bug: please report to author: Wrong len argument
kernel msg: ebtables bug: please report to author: Wrong len argument
nla_parse: 2 callbacks suppressed
netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'.
openvswitch: netlink: Flow set message rejected, Key attribute missing.
syz-executor2 uses obsolete (PF_INET,SOCK_PACKET)
netlink: 8 bytes leftover after parsing attributes in process `syz-executor0'.
openvswitch: netlink: Flow set message rejected, Key attribute missing.
netlink: 28 bytes leftover after parsing attributes in process `syz-executor5'.
netlink: 28 bytes leftover after parsing attributes in process `syz-executor5'.
FAULT_INJECTION: forcing a failure.
name fail_page_alloc, interval 1, probability 0, space 0, times 1
CPU: 1 PID: 7652 Comm: syz-executor4 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_fail_alloc_page mm/page_alloc.c:3082 [inline]
 prepare_alloc_pages mm/page_alloc.c:4322 [inline]
 __alloc_pages_nodemask+0x34e/0xd70 mm/page_alloc.c:4358
 alloc_pages_current+0x10c/0x210 mm/mempolicy.c:2093
 alloc_pages include/linux/gfp.h:492 [inline]
 skb_page_frag_refill+0x453/0x6a0 net/core/sock.c:2214
 tun_build_skb.isra.51+0x345/0x2040 drivers/net/tun.c:1631
 tun_get_user+0xc04/0x3ff0 drivers/net/tun.c:1807
 tun_chr_write_iter+0xb9/0x154 drivers/net/tun.c:1996
 call_write_iter include/linux/fs.h:1784 [inline]
 do_iter_readv_writev+0x859/0xa50 fs/read_write.c:680
 do_iter_write+0x185/0x5f0 fs/read_write.c:959
 vfs_writev+0x1c7/0x330 fs/read_write.c:1004
 do_writev+0x112/0x2f0 fs/read_write.c:1039
 __do_sys_writev fs/read_write.c:1112 [inline]
 __se_sys_writev fs/read_write.c:1109 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1109
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455831
RSP: 002b:00007f5ca1fe0ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000000007a RCX: 0000000000455831
RDX: 0000000000000001 RSI: 00007f5ca1fe0bf0 RDI: 00000000000000fc
RBP: 0000000020000100 R08: 00000000000000fc R09: 0000000000000000
R10: 000000000000007a R11: 0000000000000293 R12: 0000000000000013
R13: 0000000000000661 R14: 00000000006fc9b8 R15: 0000000000000000
netlink: 180 bytes leftover after parsing attributes in process `syz-executor3'.
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 1
CPU: 0 PID: 7709 Comm: syz-executor4 Not tainted 4.17.0-rc2+ #22
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
netlink: 180 bytes leftover after parsing attributes in process `syz-executor3'.
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 mm/slab.c:3378 [inline]
 kmem_cache_alloc+0x47/0x760 mm/slab.c:3552
 __build_skb+0xa3/0x410 net/core/skbuff.c:281
 build_skb+0x6f/0x2e0 net/core/skbuff.c:312
 tun_build_skb.isra.51+0x878/0x2040 drivers/net/tun.c:1701
 tun_get_user+0xc04/0x3ff0 drivers/net/tun.c:1807
 tun_chr_write_iter+0xb9/0x154 drivers/net/tun.c:1996
 call_write_iter include/linux/fs.h:1784 [inline]
 do_iter_readv_writev+0x859/0xa50 fs/read_write.c:680
 do_iter_write+0x185/0x5f0 fs/read_write.c:959
 vfs_writev+0x1c7/0x330 fs/read_write.c:1004
 do_writev+0x112/0x2f0 fs/read_write.c:1039
 __do_sys_writev fs/read_write.c:1112 [inline]
 __se_sys_writev fs/read_write.c:1109 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1109
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455831
RSP: 002b:00007f5ca1fe0ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000000007a RCX: 0000000000455831
RDX: 0000000000000001 RSI: 00007f5ca1fe0bf0 RDI: 00000000000000fc
RBP: 0000000020000100 R08: 00000000000000fc R09: 0000000000000000
R10: 000000000000007a R11: 0000000000000293 R12: 0000000000000013
R13: 0000000000000661 R14: 00000000006fc9b8 R15: 0000000000000001
FAULT_INJECTION: forcing a failure.
name fail_page_alloc, interval 1, probability 0, space 0, times 0
CPU: 1 PID: 7794 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_fail_alloc_page mm/page_alloc.c:3082 [inline]
 prepare_alloc_pages mm/page_alloc.c:4322 [inline]
 __alloc_pages_nodemask+0x34e/0xd70 mm/page_alloc.c:4358
netlink: 12 bytes leftover after parsing attributes in process `syz-executor2'.
 alloc_pages_current+0x10c/0x210 mm/mempolicy.c:2093
 alloc_pages include/linux/gfp.h:492 [inline]
 skb_page_frag_refill+0x453/0x6a0 net/core/sock.c:2214
 tun_build_skb.isra.51+0x345/0x2040 drivers/net/tun.c:1631
 tun_get_user+0xc04/0x3ff0 drivers/net/tun.c:1807
 tun_chr_write_iter+0xb9/0x154 drivers/net/tun.c:1996
 call_write_iter include/linux/fs.h:1784 [inline]
 do_iter_readv_writev+0x859/0xa50 fs/read_write.c:680
 do_iter_write+0x185/0x5f0 fs/read_write.c:959
 vfs_writev+0x1c7/0x330 fs/read_write.c:1004
 do_writev+0x112/0x2f0 fs/read_write.c:1039
 __do_sys_writev fs/read_write.c:1112 [inline]
 __se_sys_writev fs/read_write.c:1109 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1109
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455831
RSP: 002b:00007fecbd9beba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000000007a RCX: 0000000000455831
RDX: 0000000000000001 RSI: 00007fecbd9bebf0 RDI: 00000000000000fc
RBP: 0000000020000100 R08: 00000000000000fc R09: 0000000000000000
R10: 000000000000007a R11: 0000000000000293 R12: 0000000000000013
R13: 0000000000000661 R14: 00000000006fc9b8 R15: 0000000000000000
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 1 PID: 7866 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 mm/slab.c:3378 [inline]
 kmem_cache_alloc+0x47/0x760 mm/slab.c:3552
 __build_skb+0xa3/0x410 net/core/skbuff.c:281
 build_skb+0x6f/0x2e0 net/core/skbuff.c:312
 tun_build_skb.isra.51+0x878/0x2040 drivers/net/tun.c:1701
 tun_get_user+0xc04/0x3ff0 drivers/net/tun.c:1807
 tun_chr_write_iter+0xb9/0x154 drivers/net/tun.c:1996
 call_write_iter include/linux/fs.h:1784 [inline]
 do_iter_readv_writev+0x859/0xa50 fs/read_write.c:680
 do_iter_write+0x185/0x5f0 fs/read_write.c:959
 vfs_writev+0x1c7/0x330 fs/read_write.c:1004
 do_writev+0x112/0x2f0 fs/read_write.c:1039
 __do_sys_writev fs/read_write.c:1112 [inline]
 __se_sys_writev fs/read_write.c:1109 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1109
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455831
RSP: 002b:00007fecbd9beba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000000007a RCX: 0000000000455831
RDX: 0000000000000001 RSI: 00007fecbd9bebf0 RDI: 00000000000000fc
RBP: 0000000020000100 R08: 00000000000000fc R09: 0000000000000000
R10: 000000000000007a R11: 0000000000000293 R12: 0000000000000013
R13: 0000000000000661 R14: 00000000006fc9b8 R15: 0000000000000001