general protection fault in l2cap_sock

general protection fault in l2cap_sock_getsockopt
Status: upstream: reported C repro on 2020/02/18 04:07
Reported-by: syzbot+6446a589a5ca34dd6e8b@syzkaller.appspotmail.com
First crash: 172d, last: 172d

Cause bisection: introduced by (bisect log):

commit eab2404ba798a8efda2a970f44071c3406d94e57
Author: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Date: Fri Feb 14 18:08:57 2020 +0000

Bluetooth: Add BT_PHY socket option

Crash: general protection fault in l2cap_sock_getsockopt (log)
Repro: C syz .config

Sample crash report:

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 9844 Comm: syz-executor679 Not tainted 5.6.0-rc2-next-20200217-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:l2cap_sock_getsockopt+0x7d3/0x1200 net/bluetooth/l2cap_sock.c:613
Code: 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 a0 09 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 1f 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 75 09 00 00 48 8b 3b e8 cb be f6 ff be 67 02 00
RSP: 0018:ffffc900062f7d20 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87253e8c
RDX: 0000000000000000 RSI: ffffffff87253f44 RDI: 0000000000000001
RBP: ffffc900062f7e00 R08: ffff88808a5001c0 R09: fffffbfff16a3f80
R10: fffffbfff16a3f7f R11: ffffffff8b51fbff R12: 0000000000000000
R13: 1ffff92000c5efa7 R14: ffff8880a9a79000 R15: ffff8880a1d92000
FS:  0000000001ccd880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000140 CR3: 0000000097113000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __sys_getsockopt+0x16d/0x310 net/socket.c:2175
 __do_sys_getsockopt net/socket.c:2190 [inline]
 __se_sys_getsockopt net/socket.c:2187 [inline]
 __x64_sys_getsockopt+0xbe/0x150 net/socket.c:2187
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440149
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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcb256f088 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440149
RDX: 000000000000000e RSI: 0000000000000112 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000020000140 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019d0
R13: 0000000000401a60 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 63f0b6416dbaab7d ]---
RIP: 0010:l2cap_sock_getsockopt+0x7d3/0x1200 net/bluetooth/l2cap_sock.c:613
Code: 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 a0 09 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 1f 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 75 09 00 00 48 8b 3b e8 cb be f6 ff be 67 02 00
RSP: 0018:ffffc900062f7d20 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87253e8c
RDX: 0000000000000000 RSI: ffffffff87253f44 RDI: 0000000000000001
RBP: ffffc900062f7e00 R08: ffff88808a5001c0 R09: fffffbfff16a3f80
R10: fffffbfff16a3f7f R11: ffffffff8b51fbff R12: 0000000000000000
R13: 1ffff92000c5efa7 R14: ffff8880a9a79000 R15: ffff8880a1d92000
FS:  0000000001ccd880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000140 CR3: 0000000097113000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-linux-next-kasan-gce-root	2020/02/17 22:41	linux-next	c25a951c	2b411596	.config	log	report	syz	C	davem@davemloft.net, johan.hedberg@gmail.com, kuba@kernel.org, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, marcel@holtmann.org, netdev@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2020/02/17 22:19	linux-next	c25a951c	2b411596	.config	log	report			davem@davemloft.net, johan.hedberg@gmail.com, kuba@kernel.org, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, marcel@holtmann.org, netdev@vger.kernel.org