general protection fault in rdma_resolve_route

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: db189223 Linux 4.14.147
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=163a1dfb600000
kernel config: https://syzkaller.appspot.com/x/.config?x=14d726467704dd7
dashboard link: https://syzkaller.appspot.com/bug?extid=69226cc89d87fd4f8f40
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=118ecdb7600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13802e67600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+69226c...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 7185 Comm: syz-executor670 Not tainted 4.14.147 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
task: ffff8880a7c4c0c0 task.stack: ffff888084398000
RIP: 0010:rdma_cap_ib_sa include/rdma/ib_verbs.h:2682 [inline]
RIP: 0010:rdma_resolve_route+0x11f/0x2bf0 drivers/infiniband/core/cma.c:2678
RSP: 0018:ffff88808439fa20 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000029 RSI: 0000000000000001 RDI: 0000000000000148
RBP: ffff88808439fbc0 R08: ffff8880a7c4c0c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88809f540dc0
R13: 0000000000000000 R14: 0000000000000000 R15: ffff88809f540f78
FS: 00007f03a8778700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f03a8777e78 CR3: 000000008afd9000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ucma_resolve_route+0xab/0x100 drivers/infiniband/core/ucma.c:740
ucma_write+0x231/0x310 drivers/infiniband/core/ucma.c:1672
__vfs_write+0x105/0x6b0 fs/read_write.c:480
vfs_write+0x198/0x500 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xfd/0x230 fs/read_write.c:582
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x446a49
RSP: 002b:00007f03a8777db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 0000000000446a49
RDX: 0000000000000010 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 00000000006dbc40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00007ffea0dde3ef R14: 00007f03a87789c0 R15: 0000000000000000
Code: 00 48 c1 ea 03 80 3c 02 00 0f 85 ea 24 00 00 48 b8 00 00 00 00 00 fc
ff df 4d 8b 34 24 49 8d be 48 01 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00
0f 85 d1 24 00 00 48 b8 00 00 00 00 00 fc ff df 41
RIP: rdma_cap_ib_sa include/rdma/ib_verbs.h:2682 [inline] RSP:
ffff88808439fa20
RIP: rdma_resolve_route+0x11f/0x2bf0 drivers/infiniband/core/cma.c:2678
RSP: ffff88808439fa20
---[ end trace 6e4166af8b71ea1c ]---


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches