Hello,

syzbot hit the following crash on upstream commit
851710a8096131129ad1da79a47d385c4926d114 (Thu Mar 8 01:37:32 2018 +0000)
Merge branch 'for-linus' of  
git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

C reproducer is attached.
syzkaller reproducer is attached.
Raw console output is attached.
compiler: gcc (GCC) 7.1.1 20170620
.config is attached.

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Reported-by: syzbot+06674559539eceb4d6f0@syzkaller.appspotmail.com
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kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
    (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 10410 Comm: syzkaller958277 Not tainted 4.16.0-rc4+ #345
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:rdma_resolve_addr+0x13c/0x26c0 drivers/infiniband/core/cma.c:2921
RSP: 0018:ffff8801b3807680 EFLAGS: 00010207
RAX: 0000000000000042 RBX: ffff8801b3807a44 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8801b3807a44 RDI: 0000000000000214
RBP: ffff8801b38079e0 R08: 0000000000000000 R09: 0000000000000000
R10: ffff8801b38079f8 R11: 0000000000000000 R12: dffffc0000000000
R13: 00000000000000a0 R14: ffff8801b3807a28 R15: 0000000000000000
FS:  00007f2dc376e700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000140 CR3: 00000001c6e4e006 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  ucma_resolve_ip+0x142/0x1f0 drivers/infiniband/core/ucma.c:677
  ucma_write+0x2d6/0x3d0 drivers/infiniband/core/ucma.c:1627
  __vfs_write+0xef/0x970 fs/read_write.c:480
  vfs_write+0x189/0x510 fs/read_write.c:544
  SYSC_write fs/read_write.c:589 [inline]
  SyS_write+0xef/0x220 fs/read_write.c:581
  do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x446aa9
RSP: 002b:00007f2dc376dda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000006e29fc RCX: 0000000000446aa9
RDX: 0000000000000008 RSI: 0000000020007100 RDI: 0000000000000004
RBP: 00000000006e29f8 R08: 00007f2dc376e700 R09: 0000000000000000
R10: 00007f2dc376e700 R11: 0000000000000246 R12: 006d635f616d6472
R13: 2f646e6162696e69 R14: 666e692f7665642f R15: 0000000000000003
Code: 31 c0 e8 f8 b1 53 fd 48 89 df e8 70 f4 f5 ff 4c 89 ef 48 63 d0 48 89  
de e8 02 df 8b fd 49 8d bf 14 02 00 00 48 89 f8 48 c1 e8 03 <42> 0f b6 14  
20 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f
RIP: rdma_resolve_addr+0x13c/0x26c0 drivers/infiniband/core/cma.c:2921 RSP:  
ffff8801b3807680
---[ end trace 35b5ca64e9e3cd3f ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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