Call Trace:
kasan: CONFIG_KASAN_INLINE enabled
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
kasan: GPF could be caused by NULL-ptr deref or user memory access
 handle_userfault+0xbd9/0x2490 fs/userfaultfd.c:430
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 11112 Comm: syz-executor2 Not tainted 4.16.0-rc5+ #267
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rdma_protocol_roce include/rdma/ib_verbs.h:2546 [inline]
RIP: 0010:rdma_join_multicast+0x46d/0x3bb0 drivers/infiniband/core/cma.c:4194
RSP: 0018:ffff8801b70ef4a0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff8801d4bd9e00 RCX: 0000000000000029
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: 0000000000000148
RBP: ffff8801b70ef7a0 R08: 0000000000000000 R09: 1ffff10036e1de72
R10: ffff8801b70ef358 R11: 0000000000000001 R12: ffff8801b55c5200
R13: ffff8801d4bd9ead R14: 0000000000000000 R15: ffff8801b55c5400
FS:  0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000f77ebb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f77eac10 CR3: 00000001ced71006 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_anonymous_page mm/memory.c:3163 [inline]
 handle_pte_fault mm/memory.c:3977 [inline]
 __handle_mm_fault+0x2dfa/0x38c0 mm/memory.c:4103
 handle_mm_fault+0x44a/0xb10 mm/memory.c:4140
 ucma_process_join+0x4da/0xa90 drivers/infiniband/core/ucma.c:1375
 __do_page_fault+0x5c9/0xc90 arch/x86/mm/fault.c:1422
 ucma_join_ip_multicast+0x274/0x3b0 drivers/infiniband/core/ucma.c:1423
 do_page_fault+0xee/0x730 arch/x86/mm/fault.c:1497
 ucma_write+0x2d6/0x3d0 drivers/infiniband/core/ucma.c:1633
 page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1151
RIP: 0010:copy_user_generic_unrolled+0x86/0xc0 arch/x86/lib/copy_user_64.S:65
RSP: 0018:ffff8801da57fb48 EFLAGS: 00010202
 __vfs_write+0xef/0x970 fs/read_write.c:480
RAX: ffffed003b4aff77 RBX: 0000000020013000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000020013000 RDI: ffff8801da57fbb0
RBP: ffff8801da57fb78 R08: ffffed003b4aff77 R09: ffffed003b4aff77
R10: 0000000000000001 R11: ffffed003b4aff76 R12: 0000000000000008
R13: ffff8801da57fbb0 R14: 00007ffffffff000 R15: 0000000020013008
 copy_from_user include/linux/uaccess.h:147 [inline]
 __compat_get_timespec64 kernel/compat.c:129 [inline]
 compat_get_timespec64+0x124/0x240 kernel/compat.c:154
 do_compat_pselect fs/select.c:1315 [inline]
 C_SYSC_pselect6 fs/select.c:1368 [inline]
 compat_SyS_pselect6+0x190/0x630 fs/select.c:1353
 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_32_irqs_on arch/x86/entry/common.c:330 [inline]
 do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f91c99
RSP: 002b:00000000f778d09c EFLAGS: 00000286
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
 ORIG_RAX: 0000000000000134
RIP: 0023:0xf7fefc99
RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 0000000020011fc0
RSP: 002b:00000000f77eb09c EFLAGS: 00000286
RDX: 0000000020011000 RSI: 0000000020003000 RDI: 0000000020013000
 ORIG_RAX: 0000000000000004
RBP: 0000000020001ff8 R08: 0000000000000000 R09: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020000100
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
RDX: 0000000000000038 RSI: 0000000000000000 RDI: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Code: 00 48 c1 ea 03 80 3c 02 00 0f 85 d7 34 00 00 49 8b 04 24 48 ba 00 00 00 00 00 fc ff df 48 8d b8 48 01 00 00 48 89 f9 48 c1 e9 03 <80> 3c 11 00 0f 85 f5 35 00 00 49 c1 e6 04 4c 03 b0 48 01 00 00 
RIP: rdma_protocol_roce include/rdma/ib_verbs.h:2546 [inline] RSP: ffff8801b70ef4a0
RIP: rdma_join_multicast+0x46d/0x3bb0 drivers/infiniband/core/cma.c:4194 RSP: ffff8801b70ef4a0
---[ end trace 0e6a828ece50c5f9 ]---