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

syzbot
2025-02-20T16:00:25Z

Hello,

syzbot found the following issue on:

HEAD commit: e5d3fd687aac Add linux-next specific files for 20250218
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=152ae5b0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4e945b2fe8e5992f
dashboard link: https://syzkaller.appspot.com/bug?extid=9c957444e37d521b3b94
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=12b0a498580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=178577df980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ef079ccd2725/disk-e5d3fd68.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/99f2123d6831/vmlinux-e5d3fd68.xz
kernel image: https://storage.googleapis.com/syzbot-assets/eadfc9520358/bzImage-e5d3fd68.xz

The issue was bisected to:

commit 3ca66179e56d25f1e3ed1608241abb487c63e9b7
Author: Arseniy Krasnov <avkrasnov@salutedevices.com>
Date: Thu Jan 30 18:43:26 2025 +0000

Bluetooth: hci_uart: fix race during initialization

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=164e1498580000
final oops: https://syzkaller.appspot.com/x/report.txt?x=154e1498580000
console output: https://syzkaller.appspot.com/x/log.txt?x=114e1498580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9c957444e37d521b3b94@syzkaller.appspotmail.com
Fixes: 3ca66179e56d ("Bluetooth: hci_uart: fix race during initialization")

RBP: 0000000000000001 R08: 00007ffc19740607 R09: 00007f7d8d9301a8
R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffc1974088c
R13: 00007ffc197408d0 R14: 00007ffc197408b0 R15: 0000000000000006
</TASK>
Bluetooth: Can't allocate HCI device
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000029: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000148-0x000000000000014f]
CPU: 1 UID: 0 PID: 5841 Comm: syz-executor246 Not tainted 6.14.0-rc3-next-20250218-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:__lock_acquire+0x6a/0x2100 kernel/locking/lockdep.c:5091
Code: b6 04 30 84 c0 0f 85 f8 16 00 00 45 31 f6 83 3d 2b c3 a0 0e 00 0f 84 c8 13 00 00 89 54 24 60 89 5c 24 38 4c 89 f8 48 c1 e8 03 <80> 3c 30 00 74 12 4c 89 ff e8 58 6c 8c 00 48 be 00 00 00 00 00 fc
RSP: 0018:ffffc90003e2f6d0 EFLAGS: 00010002
RAX: 0000000000000029 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 0000000000000148
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff207b48f R12: ffff88803482da00
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000148
FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7d8d9ca243 CR3: 000000000e938000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
__timer_delete_sync+0x148/0x310 kernel/time/timer.c:1644
bcsp_close+0x4c/0x130 drivers/bluetooth/hci_bcsp.c:740
hci_uart_tty_close+0x205/0x290 drivers/bluetooth/hci_ldisc.c:557
tty_ldisc_kill+0xa3/0x1a0 drivers/tty/tty_ldisc.c:613
tty_ldisc_release+0x1a1/0x200 drivers/tty/tty_ldisc.c:781
tty_release_struct+0x2b/0xe0 drivers/tty/tty_io.c:1690
tty_release+0xd06/0x12c0 drivers/tty/tty_io.c:1861
__fput+0x3e9/0x9f0 fs/file_table.c:464
task_work_run+0x24f/0x310 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0xa2a/0x28e0 kernel/exit.c:952
do_group_exit+0x207/0x2c0 kernel/exit.c:1101
__do_sys_exit_group kernel/exit.c:1112 [inline]
__se_sys_exit_group kernel/exit.c:1110 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1110
x64_sys_call+0x26c3/0x26d0 arch/x86/include/generated/asm/syscalls_64.h:232
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: 0033:0x7f7d8d972b79
Code: Unable to access opcode bytes at 0x7f7d8d972b4f.
RSP: 002b:00007ffc19740808 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7d8d972b79
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 00007f7d8d9e6350 R08: ffffffffffffffb8 R09: 00007f7d8d9301a8
R10: 0000000000000001 R11: 0000000000000246 R12: 00007f7d8d9e6350
R13: 0000000000000000 R14: 00007f7d8d9e6da0 R15: 00007f7d8d93c220
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__lock_acquire+0x6a/0x2100 kernel/locking/lockdep.c:5091
Code: b6 04 30 84 c0 0f 85 f8 16 00 00 45 31 f6 83 3d 2b c3 a0 0e 00 0f 84 c8 13 00 00 89 54 24 60 89 5c 24 38 4c 89 f8 48 c1 e8 03 <80> 3c 30 00 74 12 4c 89 ff e8 58 6c 8c 00 48 be 00 00 00 00 00 fc
RSP: 0018:ffffc90003e2f6d0 EFLAGS: 00010002
RAX: 0000000000000029 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 0000000000000148
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff207b48f R12: ffff88803482da00
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000148
FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7d8d9ca243 CR3: 000000000e938000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: b6 04 mov $0x4,%dh
2: 30 84 c0 0f 85 f8 16 xor %al,0x16f8850f(%rax,%rax,8)
9: 00 00 add %al,(%rax)
b: 45 31 f6 xor %r14d,%r14d
e: 83 3d 2b c3 a0 0e 00 cmpl $0x0,0xea0c32b(%rip) # 0xea0c340
15: 0f 84 c8 13 00 00 je 0x13e3
1b: 89 54 24 60 mov %edx,0x60(%rsp)
1f: 89 5c 24 38 mov %ebx,0x38(%rsp)
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 30 00 cmpb $0x0,(%rax,%rsi,1) <-- trapping instruction
2e: 74 12 je 0x42
30: 4c 89 ff mov %r15,%rdi
33: e8 58 6c 8c 00 call 0x8c6c90
38: 48 rex.W
39: be 00 00 00 00 mov $0x0,%esi
3e: 00 fc add %bh,%ah

---
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