[moderation] [bluetooth?] general protection fault in l2cap_conn_del (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 785f0eb2f85d Add linux-next specific files for 20260320
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13df4b52580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c584910d0d74158d
dashboard link: https://syzkaller.appspot.com/bug?extid=ba95575894f00ef7ff71
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [linux-b...@vger.kernel.org linux-...@vger.kernel.org luiz....@gmail.com mar...@holtmann.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a1f7fd9c1a63/disk-785f0eb2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6c138da87c25/vmlinux-785f0eb2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4d1be64e56db/bzImage-785f0eb2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ba9557...@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000020: 0000 [#1] SMP KASAN PTI
KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107]
CPU: 1 UID: 0 PID: 10553 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:l2cap_conn_del+0x2cc/0x5c0 net/bluetooth/l2cap_core.c:1797
Code: 00 4c 89 e0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 e7 e8 48 77 7f f7 4d 8b 2c 24 4d 39 e5 0f 84 f8 00 00 00 4c 89 e8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ef e8 26 77 7f f7 49 8b 6d 00 4d 8d bd 80
RSP: 0018:ffffc90005edf9f0 EFLAGS: 00010a02
RAX: 1bd5a00000000020 RBX: dffffc0000000000 RCX: ffff8880316f5b80
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: dead000000000100 R08: ffff88802c3af00b R09: 1ffff11005875e01
R10: dffffc0000000000 R11: ffffed1005875e02 R12: ffff888078b52288
R13: dead000000000100 R14: ffff88802c3af4b0 R15: ffff88802c3af000
FS: 0000000000000000(0000) GS:ffff888125548000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0216c19000 CR3: 000000005ac48000 CR4: 00000000003526f0
Call Trace:
<TASK>
hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline]
hci_conn_hash_flush+0x10d/0x260 net/bluetooth/hci_conn.c:2644
hci_dev_close_sync+0x821/0x10e0 net/bluetooth/hci_sync.c:5358
hci_dev_do_close net/bluetooth/hci_core.c:502 [inline]
hci_unregister_dev+0x21a/0x5a0 net/bluetooth/hci_core.c:2716
vhci_release+0x152/0x1a0 drivers/bluetooth/hci_vhci.c:690
__fput+0x451/0x8c0 fs/file_table.c:500
task_work_run+0x1d9/0x270 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x926/0x2490 kernel/exit.c:974
do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
__do_sys_exit_group kernel/exit.c:1127 [inline]
__se_sys_exit_group kernel/exit.c:1125 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1125
x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1f0a59c799
Code: Unable to access opcode bytes at 0x7f1f0a59c76f.
RSP: 002b:00007fff5c951ea8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f1f0a632075 RCX: 00007f1f0a59c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f1f0a632050
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff5c953160
R13: 00007f1f0a632050 R14: 00000000000a8875 R15: 00007fff5c955320
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:l2cap_conn_del+0x2cc/0x5c0 net/bluetooth/l2cap_core.c:1797
Code: 00 4c 89 e0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 e7 e8 48 77 7f f7 4d 8b 2c 24 4d 39 e5 0f 84 f8 00 00 00 4c 89 e8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ef e8 26 77 7f f7 49 8b 6d 00 4d 8d bd 80
RSP: 0018:ffffc90005edf9f0 EFLAGS: 00010a02
RAX: 1bd5a00000000020 RBX: dffffc0000000000 RCX: ffff8880316f5b80
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: dead000000000100 R08: ffff88802c3af00b R09: 1ffff11005875e01
R10: dffffc0000000000 R11: ffffed1005875e02 R12: ffff888078b52288
R13: dead000000000100 R14: ffff88802c3af4b0 R15: ffff88802c3af000
FS: 0000000000000000(0000) GS:ffff888125448000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f00e95d7e9c CR3: 000000006a556000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 00 4c 89 e0 add %cl,-0x20(%rcx,%rcx,4)
4: 48 c1 e8 03 shr $0x3,%rax
8: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1)
c: 74 08 je 0x16
e: 4c 89 e7 mov %r12,%rdi
11: e8 48 77 7f f7 call 0xf77f775e
16: 4d 8b 2c 24 mov (%r12),%r13
1a: 4d 39 e5 cmp %r12,%r13
1d: 0f 84 f8 00 00 00 je 0x11b
23: 4c 89 e8 mov %r13,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 ef mov %r13,%rdi
33: e8 26 77 7f f7 call 0xf77f775e
38: 49 8b 6d 00 mov 0x0(%r13),%rbp
3c: 4d rex.WRB
3d: 8d .byte 0x8d
3e: bd .byte 0xbd
3f: 80 .byte 0x80


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