kernel BUG at drivers/android/binder_alloc.c:LINE! (2)

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit:    b3418f8bddf4 Add linux-next specific files for 20190214
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12ccad60c00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8a3a37525a677c71
dashboard link: https://syzkaller.appspot.com/bug?extid=55de1eb4975dec156d8f
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16f63047400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12a2ed58c00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+55de1eb4975dec156d8f at syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at drivers/android/binder_alloc.c:1141!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 7540 Comm: syz-executor013 Not tainted 5.0.0-rc6-next-20190214  
#35
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:binder_alloc_do_buffer_copy+0xd6/0x510  
drivers/android/binder_alloc.c:1141
Code: 02 00 0f 85 20 04 00 00 4d 8b 64 24 58 49 29 dc e8 9f e1 26 fc 4c 89  
e6 4c 89 ef e8 b4 e2 26 fc 4d 39 e5 76 07 e8 8a e1 26 fc <0f> 0b e8 83 e1  
26 fc 4c 8b 75 d0 4d 29 ec 4c 89 e6 4c 89 f7 e8 91
RSP: 0018:ffff88804a6cf558 EFLAGS: 00010293
RAX: ffff888033dc61c0 RBX: 0000000020001000 RCX: ffffffff8549806c
RDX: 0000000000000000 RSI: ffffffff85498076 RDI: 0000000000000006
RBP: ffff88804a6cf5d8 R08: ffff888033dc61c0 R09: 0000000000000028
R10: ffffed10094d9f01 R11: ffff88804a6cf80f R12: 0000000000000008
R13: 0000000000000028 R14: ffff888069c1c210 R15: 0000000000000000
FS:  00000000017d9940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007b49a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  binder_alloc_copy_from_buffer+0x37/0x42 drivers/android/binder_alloc.c:1187
  binder_get_object+0xa2/0x1e0 drivers/android/binder.c:2062
  binder_transaction+0x2b4a/0x6690 drivers/android/binder.c:3231
  binder_thread_write+0x64a/0x2820 drivers/android/binder.c:3792
  binder_ioctl_write_read drivers/android/binder.c:4825 [inline]
  binder_ioctl+0x1033/0x183b drivers/android/binder.c:5002
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:509 [inline]
  do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
  ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
  __do_sys_ioctl fs/ioctl.c:720 [inline]
  __se_sys_ioctl fs/ioctl.c:718 [inline]
  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x444579
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 7b d8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff3621c708 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fff3621c710 RCX: 0000000000444579
RDX: 0000000020000440 RSI: 00000000c0306201 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000401000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402280
R13: 0000000000402310 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace e53003f51f970669 ]---
RIP: 0010:binder_alloc_do_buffer_copy+0xd6/0x510  
drivers/android/binder_alloc.c:1141
Code: 02 00 0f 85 20 04 00 00 4d 8b 64 24 58 49 29 dc e8 9f e1 26 fc 4c 89  
e6 4c 89 ef e8 b4 e2 26 fc 4d 39 e5 76 07 e8 8a e1 26 fc <0f> 0b e8 83 e1  
26 fc 4c 8b 75 d0 4d 29 ec 4c 89 e6 4c 89 f7 e8 91
RSP: 0018:ffff88804a6cf558 EFLAGS: 00010293
RAX: ffff888033dc61c0 RBX: 0000000020001000 RCX: ffffffff8549806c
RDX: 0000000000000000 RSI: ffffffff85498076 RDI: 0000000000000006
RBP: ffff88804a6cf5d8 R08: ffff888033dc61c0 R09: 0000000000000028
R10: ffffed10094d9f01 R11: ffff88804a6cf80f R12: 0000000000000008
R13: 0000000000000028 R14: ffff888069c1c210 R15: 0000000000000000
FS:  00000000017d9940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007b49a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400