[syzbot] [bluetooth?] general protection fault in h4_recv

[syzbot <syzbot+ff30eeab8e07b37d524e@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    3aae9383f42f Merge tag 'input-for-v7.0-rc6' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17814e06580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5a3e5e8c17cc174e
dashboard link: https://syzkaller.appspot.com/bug?extid=ff30eeab8e07b37d524e
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=108c0bd6580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11015d02580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/46384525f287/disk-3aae9383.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bcd9d5c20ab7/vmlinux-3aae9383.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e4353e5e60e2/bzImage-3aae9383.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ff30eeab8e07b37d524e@syzkaller.appspotmail.com

RBP: 00007ffeca659d70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fd7d4415fac R14: 00007fd7d4415fa0 R15: 00007fd7d4415fa0
 </TASK>
Bluetooth: Can't register HCI device
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 5964 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:h4_recv+0x52/0x1c0 drivers/bluetooth/hci_h4.c:112
Code: df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 3c 01 00 00 4c 8b a3 b8 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 31 01 00 00 49 8b 34 24 48 89 ea 41 b9 04 00 00
RSP: 0018:ffffc900037afca8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff888033b48400 RCX: ffffffff887767b0
RDX: 0000000000000000 RSI: ffffffff8877b6a8 RDI: ffff888033b485b8
RBP: ffffc900037afd68 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: ffff888033b484c0 R15: ffffffff8cc1b1c0
FS:  000055556677d500(0000) GS:ffff888124339000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd7d4072140 CR3: 00000000747cb000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 hci_uart_tty_receive+0x259/0x7e0 drivers/bluetooth/hci_ldisc.c:627
 tiocsti drivers/tty/tty_io.c:2290 [inline]
 tty_ioctl+0x909/0x1690 drivers/tty/tty_io.c:2706
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd7d419c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeca659d08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd7d4415fa0 RCX: 00007fd7d419c819
RDX: 0000200000000100 RSI: 0000000000005412 RDI: 0000000000000003
RBP: 00007fd7d4232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd7d4415fac R14: 00007fd7d4415fa0 R15: 00007fd7d4415fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:h4_recv+0x52/0x1c0 drivers/bluetooth/hci_h4.c:112
Code: df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 3c 01 00 00 4c 8b a3 b8 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 31 01 00 00 49 8b 34 24 48 89 ea 41 b9 04 00 00
RSP: 0018:ffffc900037afca8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff888033b48400 RCX: ffffffff887767b0
RDX: 0000000000000000 RSI: ffffffff8877b6a8 RDI: ffff888033b485b8
RBP: ffffc900037afd68 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: ffff888033b484c0 R15: ffffffff8cc1b1c0
FS:  000055556677d500(0000) GS:ffff888124339000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd7d4072140 CR3: 00000000747cb000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	df 48 89             	fisttps -0x77(%rax)
   3:	fa                   	cli
   4:	48 c1 ea 03          	shr    $0x3,%rdx
   8:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   c:	0f 85 3c 01 00 00    	jne    0x14e
  12:	4c 8b a3 b8 01 00 00 	mov    0x1b8(%rbx),%r12
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  23:	4c 89 e2             	mov    %r12,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 31 01 00 00    	jne    0x165
  34:	49 8b 34 24          	mov    (%r12),%rsi
  38:	48 89 ea             	mov    %rbp,%rdx
  3b:	41                   	rex.B
  3c:	b9                   	.byte 0xb9
  3d:	04 00                	add    $0x0,%al


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