[syzbot] [bluetooth?] general protection fault in sco_conn_add

[syzbot] [bluetooth?] general protection fault in sco_conn_add

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3674fbf0451d Merge git://git.kernel.org/pub/scm/linux/kern..
git tree:       net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13ab3f4f280000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c9bf1936936ca698
dashboard link: https://syzkaller.appspot.com/bug?extid=37acd5d80d00d609d233
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1049b4e2a80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=171aa228a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/42ed556782c3/disk-3674fbf0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1913e16e8565/vmlinux-3674fbf0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/469804b58a7c/bzImage-3674fbf0.xz

The issue was bisected to:

commit 06149746e7203d5ffe2d6faf9799ee36203aa8b8
Author: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Date:   Tue Apr 11 23:02:22 2023 +0000

    Bluetooth: hci_conn: Add support for linking multiple hcon

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=148e6b08a80000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=168e6b08a80000
console output: https://syzkaller.appspot.com/x/log.txt?x=128e6b08a80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+37acd5d80d00d609d233@syzkaller.appspotmail.com
Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon")

RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f09bc777879
RDX: 0000000000000008 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000800000015
R10: 0000000000000000 R11: 0000000000000246 R12: 0000555555a6d2b8
R13: 00007ffe17db6850 R14: 0000000000000072 R15: 00007ffe17db6860
 </TASK>
general protection fault, probably for non-canonical address 0xdffffc000000013b: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000009d8-0x00000000000009df]
CPU: 1 PID: 5013 Comm: syz-executor238 Not tainted 6.4.0-rc7-syzkaller-01944-g3674fbf0451d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
RIP: 0010:sco_conn_add+0x2a/0x330 net/bluetooth/sco.c:127
Code: 41 57 41 56 41 55 49 89 fd 41 54 55 49 8d ad d8 09 00 00 53 e8 b7 f1 5a f8 48 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 8b 02 00 00 4d 8b a5 d8 09 00 00 4d 85 e4 74 13
RSP: 0018:ffffc90003a8fd50 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888028830000 RCX: 0000000000000000
RDX: 000000000000013b RSI: ffffffff892957a9 RDI: 0000000000000000
RBP: 00000000000009d8 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8880203cf540 R15: ffff888028830010
FS:  0000555555a6d300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f09bc7db6e3 CR3: 0000000025e98000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 sco_connect net/bluetooth/sco.c:274 [inline]
 sco_sock_connect+0x321/0xae0 net/bluetooth/sco.c:610
 __sys_connect_file+0x153/0x1a0 net/socket.c:1991
 __sys_connect+0x165/0x1a0 net/socket.c:2008
 __do_sys_connect net/socket.c:2018 [inline]
 __se_sys_connect net/socket.c:2015 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:2015
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f09bc777879
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 18 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe17db67f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f09bc777879
RDX: 0000000000000008 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000800000015
R10: 0000000000000000 R11: 0000000000000246 R12: 0000555555a6d2b8
R13: 00007ffe17db6850 R14: 0000000000000072 R15: 00007ffe17db6860
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:sco_conn_add+0x2a/0x330 net/bluetooth/sco.c:127
Code: 41 57 41 56 41 55 49 89 fd 41 54 55 49 8d ad d8 09 00 00 53 e8 b7 f1 5a f8 48 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 8b 02 00 00 4d 8b a5 d8 09 00 00 4d 85 e4 74 13
RSP: 0018:ffffc90003a8fd50 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888028830000 RCX: 0000000000000000
RDX: 000000000000013b RSI: ffffffff892957a9 RDI: 0000000000000000
RBP: 00000000000009d8 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8880203cf540 R15: ffff888028830010
FS:  0000555555a6d300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005653cab3d008 CR3: 0000000025e98000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	41 57                	push   %r15
   2:	41 56                	push   %r14
   4:	41 55                	push   %r13
   6:	49 89 fd             	mov    %rdi,%r13
   9:	41 54                	push   %r12
   b:	55                   	push   %rbp
   c:	49 8d ad d8 09 00 00 	lea    0x9d8(%r13),%rbp
  13:	53                   	push   %rbx
  14:	e8 b7 f1 5a f8       	callq  0xf85af1d0
  19:	48 89 ea             	mov    %rbp,%rdx
  1c:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  23:	fc ff df
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 8b 02 00 00    	jne    0x2bf
  34:	4d 8b a5 d8 09 00 00 	mov    0x9d8(%r13),%r12
  3b:	4d 85 e4             	test   %r12,%r12
  3e:	74 13                	je     0x53


---
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

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Re: [syzbot] [bluetooth?] general protection fault in sco_conn_add

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+37acd5d80d00d609d233@syzkaller.appspotmail.com

Tested on:

commit:         3674fbf0 Merge git://git.kernel.org/pub/scm/linux/kern..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git
console output: https://syzkaller.appspot.com/x/log.txt?x=161333e8a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c9bf1936936ca698
dashboard link: https://syzkaller.appspot.com/bug?extid=37acd5d80d00d609d233
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch:          https://syzkaller.appspot.com/x/patch.diff?x=167f9074a80000

Note: testing is done by a robot and is best-effort only.