Date:   Mon, 18 Dec 2017 08:23:01 -0800
From:   syzbot 
        <bot+35deca9d7b3505582b66105c21fb8ee54bc79554@...kaller.appspotmail.com>
To:     arve@...roid.com, devel@...verdev.osuosl.org,
        gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
        maco@...roid.com, syzkaller-bugs@...glegroups.com,
        tkjos@...roid.com
Subject: BUG: unable to handle kernel NULL pointer dereference in binder_poll

Hello,

syzkaller hit the following crash on  
6084b576dca2e898f5c101baef151f7bfdbb606d
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
C reproducer is attached
syzkaller reproducer is attached. See https://goo.gl/kgGztJ
for information about syzkaller reproducers


RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000444119
RDX: 0000000000000004 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000032
R10: 00000000207a6000 R11: 0000000000000246 R12: 0000000000401e60
R13: 0000000000401ef0 R14: 0000000000000000 R15: 0000000000000000
BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: binder_poll+0x28/0xf0 drivers/android/binder.c:4371
PGD 2134c1067 P4D 2134c1067 PUD 214180067 PMD 0
Oops: 0000 [#1] SMP
Dumping ftrace buffer:
    (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 3117 Comm: syzkaller406906 Not tainted  
4.15.0-rc3-next-20171214+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:binder_poll+0x28/0xf0 drivers/android/binder.c:4371
RSP: 0018:ffffc900017d3df0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffffc900017d3ef0 RCX: ffffffff820258f3
RDX: 0000000000000000 RSI: ffffffff83080700 RDI: 0000000000000286
RBP: ffffc900017d3e20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc900017d3ef0
R13: ffff8802118fb000 R14: ffffffff82bb9f20 R15: ffff8802140d1c30
FS:  0000000000deb880(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000216bbc002 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  ep_item_poll.isra.10+0x49/0xf0 fs/eventpoll.c:885
  ep_insert fs/eventpoll.c:1457 [inline]
  SYSC_epoll_ctl fs/eventpoll.c:2104 [inline]
  SyS_epoll_ctl+0x884/0x1010 fs/eventpoll.c:1990
  entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x444119
RSP: 002b:00007fffbc6b55b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000444119
RDX: 0000000000000004 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000032
R10: 00000000207a6000 R11: 0000000000000246 R12: 0000000000401e60
R13: 0000000000401ef0 R14: 0000000000000000 R15: 0000000000000000
Code: ff 66 90 55 48 89 e5 41 57 41 56 41 55 41 54 49 89 fd 53 49 89 f4 48  
83 ec 08 e8 24 49 29 ff 49 8b bd 90 01 00 00 e8 78 fd ff ff <48> 8b 38 48  
89 c3 be 15 11 00 00 e8 e8 7e ff ff 44 8b 73 34 44
RIP: binder_poll+0x28/0xf0 drivers/android/binder.c:4371 RSP:  
ffffc900017d3df0
CR2: 0000000000000000
---[ end trace 0049f47570a6b8eb ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
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View attachment "config.txt" of type "text/plain" (126475 bytes)

Download attachment "raw.log" of type "application/octet-stream" (5726 bytes)

View attachment "repro.txt" of type "text/plain" (437 bytes)

Download attachment "repro.c" of type "application/octet-stream" (2709 bytes)

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