Re: [syzbot] [bluetooth?] general protection fault in h5_recv

[syzbot <syzbot+b5691bb559396b262064@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    df5d6180169a Add linux-next specific files for 20250210
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14a9c3f8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7
dashboard link: https://syzkaller.appspot.com/bug?extid=b5691bb559396b262064
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=149c78e4580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=129c78e4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/92495cf20271/disk-df5d6180.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4b3656161842/vmlinux-df5d6180.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7fbc4e7a0f5d/bzImage-df5d6180.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b5691bb559396b262064@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc000000005f: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000002f8-0x00000000000002ff]
CPU: 1 UID: 0 PID: 5834 Comm: syz-executor200 Not tainted 6.14.0-rc2-next-20250210-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:h5_recv+0x153/0x940 drivers/bluetooth/hci_h5.c:572
Code: 08 01 44 8b 64 24 04 48 8b 5c 24 08 4c 8b 74 24 18 49 ff c7 41 ff cc 45 85 e4 0f 8e 55 06 00 00 e8 a2 58 f5 f8 48 8b 44 24 30 <42> 80 3c 28 00 74 08 48 89 df e8 ce 53 5c f9 48 8b 1b 31 ff 48 89
RSP: 0018:ffffc90003e8fc60 EFLAGS: 00010202
RAX: 000000000000005f RBX: 00000000000002f8 RCX: 0000000000000061
RDX: ffff8880350dda00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003e8fd70 R08: ffffffff88ca308e R09: 1ffff110062cdb03
R10: dffffc0000000000 R11: ffffffff88ca2fd0 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88803166d800 R15: ffffc90003e8fe00
FS:  00007f38f1dd06c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f38f1d8ed58 CR3: 000000007b704000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 hci_uart_tty_receive+0x141/0x1c0 drivers/bluetooth/hci_ldisc.c:622
 tiocsti+0x24d/0x300 drivers/tty/tty_io.c:2299
 tty_ioctl+0x518/0xdc0 drivers/tty/tty_io.c:2716
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f38f1e183d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f38f1dd0218 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f38f1e9f328 RCX: 00007f38f1e183d9
RDX: 0000400000000040 RSI: 0000000000005412 RDI: 0000000000000006
RBP: 00007f38f1e9f320 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f38f1e6c074
R13: 0000400000000300 R14: 00004000000000c0 R15: 0000400000000040
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:h5_recv+0x153/0x940 drivers/bluetooth/hci_h5.c:572
Code: 08 01 44 8b 64 24 04 48 8b 5c 24 08 4c 8b 74 24 18 49 ff c7 41 ff cc 45 85 e4 0f 8e 55 06 00 00 e8 a2 58 f5 f8 48 8b 44 24 30 <42> 80 3c 28 00 74 08 48 89 df e8 ce 53 5c f9 48 8b 1b 31 ff 48 89
RSP: 0018:ffffc90003e8fc60 EFLAGS: 00010202
RAX: 000000000000005f RBX: 00000000000002f8 RCX: 0000000000000061
RDX: ffff8880350dda00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003e8fd70 R08: ffffffff88ca308e R09: 1ffff110062cdb03
R10: dffffc0000000000 R11: ffffffff88ca2fd0 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88803166d800 R15: ffffc90003e8fe00
FS:  00007f38f1dd06c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000040000000f000 CR3: 000000007b704000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	08 01                	or     %al,(%rcx)
   2:	44 8b 64 24 04       	mov    0x4(%rsp),%r12d
   7:	48 8b 5c 24 08       	mov    0x8(%rsp),%rbx
   c:	4c 8b 74 24 18       	mov    0x18(%rsp),%r14
  11:	49 ff c7             	inc    %r15
  14:	41 ff cc             	dec    %r12d
  17:	45 85 e4             	test   %r12d,%r12d
  1a:	0f 8e 55 06 00 00    	jle    0x675
  20:	e8 a2 58 f5 f8       	call   0xf8f558c7
  25:	48 8b 44 24 30       	mov    0x30(%rsp),%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 ce 53 5c f9       	call   0xf95c5407
  39:	48 8b 1b             	mov    (%rbx),%rbx
  3c:	31 ff                	xor    %edi,%edi
  3e:	48                   	rex.W
  3f:	89                   	.byte 0x89


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