BUG: unable to handle kernel paging request in rfcomm_dlc_exists

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 31cc088a Merge tag 'drm-next-2019-07-19' of git://anongit...
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1483100c600000
kernel config: https://syzkaller.appspot.com/x/.config?x=4dba67bf8b8c9ad7
dashboard link: https://syzkaller.appspot.com/bug?extid=ffdf3361e133d6320812
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [da...@davemloft.net gus...@embeddedor.com
johan....@gmail.com kees...@chromium.org
linux-b...@vger.kernel.org linux-...@vger.kernel.org
mar...@holtmann.org net...@vger.kernel.org tiny....@gmail.com
net...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ffdf33...@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: ffffffffffff0144
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 8c70067 P4D 8c70067 PUD 8c72067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7906 Comm: syz-executor.1 Not tainted 5.2.0+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline]
RIP: 0010:rfcomm_dlc_exists+0x13b/0x1a0 net/bluetooth/rfcomm/core.c:550
Code: f4 74 55 e8 f7 c1 f7 fa 49 8d bc 24 44 01 00 00 48 89 f8 48 89 fa 48
c1 e8 03 83 e2 07 42 0f b6 04 28 38 d0 7f 04 84 c0 75 3d <45> 0f b6 bc 24
44 01 00 00 89 df 44 89 fe e8 82 c2 f7 fa 44 38 fb
RSP: 0018:ffff8880566279c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 000000000000000d RCX: ffffc900081fe000
RDX: 0000000000000004 RSI: ffffffff867ac2e9 RDI: ffffffffffff0144
RBP: ffff8880566279e8 R08: ffff88804e200040 R09: fffffbfff1314cf1
R10: ffff8880566279b0 R11: ffffffff898a6787 R12: ffffffffffff0000
R13: dffffc0000000000 R14: ffff88809bf4c980 R15: 0000000000000000
FS: 00007f19cf9de700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffff0144 CR3: 00000000a0404000 CR4: 00000000001406e0
Call Trace:
__rfcomm_create_dev net/bluetooth/rfcomm/tty.c:413 [inline]
rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline]
rfcomm_dev_ioctl+0x5ab/0x1b80 net/bluetooth/rfcomm/tty.c:588
rfcomm_sock_ioctl+0x90/0xb0 net/bluetooth/rfcomm/sock.c:902
sock_do_ioctl+0xd8/0x2f0 net/socket.c:1038
sock_ioctl+0x3ed/0x790 net/socket.c:1189
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xdb6/0x13e0 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+0xfd/0x6a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f19cf9ddc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f19cf9de6d4
R13: 00000000004c1f76 R14: 00000000004d5240 R15: 00000000ffffffff
Modules linked in:
CR2: ffffffffffff0144
---[ end trace 59eeead9cd9bdc59 ]---
RIP: 0010:rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline]
RIP: 0010:rfcomm_dlc_exists+0x13b/0x1a0 net/bluetooth/rfcomm/core.c:550
Code: f4 74 55 e8 f7 c1 f7 fa 49 8d bc 24 44 01 00 00 48 89 f8 48 89 fa 48
c1 e8 03 83 e2 07 42 0f b6 04 28 38 d0 7f 04 84 c0 75 3d <45> 0f b6 bc 24
44 01 00 00 89 df 44 89 fe e8 82 c2 f7 fa 44 38 fb
RSP: 0018:ffff8880566279c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 000000000000000d RCX: ffffc900081fe000
RDX: 0000000000000004 RSI: ffffffff867ac2e9 RDI: ffffffffffff0144
RBP: ffff8880566279e8 R08: ffff88804e200040 R09: fffffbfff1314cf1
R10: ffff8880566279b0 R11: ffffffff898a6787 R12: ffffffffffff0000
R13: dffffc0000000000 R14: ffff88809bf4c980 R15: 0000000000000000
FS: 00007f19cf9de700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffff0144 CR3: 00000000a0404000 CR4: 00000000001406e0


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.