linux-kernel - [syzbot] [bluetooth] stack segment fault in kernfs_rename

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Message-ID: <687c6966.a70a0220.693ce.00a5.GAE@google.com>
Date: Sat, 19 Jul 2025 20:58:30 -0700
From: syzbot <syzbot+d1db96f72a452dc9cbd2@...kaller.appspotmail.com>
To: gregkh@...uxfoundation.org, linux-bluetooth@...r.kernel.org, 
	linux-kernel@...r.kernel.org, luiz.dentz@...il.com, marcel@...tmann.org, 
	netdev@...r.kernel.org, syzkaller-bugs@...glegroups.com, tj@...nel.org
Subject: [syzbot] [bluetooth] stack segment fault in kernfs_rename_ns

Hello,

syzbot found the following issue on:

HEAD commit:    b9fd9888a565 bnxt_en: eliminate the compile warning in bnx..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=118ce582580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b29b1a0d7330d4a8
dashboard link: https://syzkaller.appspot.com/bug?extid=d1db96f72a452dc9cbd2
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/01ea776e1c9e/disk-b9fd9888.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bba0c9444631/vmlinux-b9fd9888.xz
kernel image: https://storage.googleapis.com/syzbot-assets/810cd37cc085/bzImage-b9fd9888.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d1db96f72a452dc9cbd2@...kaller.appspotmail.com

Oops: stack segment: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6246 Comm: syz.3.81 Not tainted 6.16.0-rc4-syzkaller-00109-gb9fd9888a565 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:kernfs_rename_ns+0x3a/0x7a0 fs/kernfs/dir.c:1747
Code: ec 48 48 89 cb 48 89 54 24 10 49 89 f5 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 d1 5b 62 ff 4d 8d 7e 30 4c 89 fd 48 c1 ed 03 <42> 80 7c 25 00 00 74 08 4c 89 ff e8 86 de c5 ff 49 83 3f 00 0f 84
RSP: 0018:ffffc90003ecf9c0 EFLAGS: 00010206
RAX: ffffffff825e02cf RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000cbbb000 RSI: 0000000000000873 RDI: 0000000000000874
RBP: 0000000000000006 R08: ffff88801c7e9e00 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000002 R12: dffffc0000000000
R13: ffff888143acf960 R14: 0000000000000000 R15: 0000000000000030
FS:  00007fb14932a6c0(0000) GS:ffff888125c1d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000009e000 CR3: 000000007d24a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 kobject_move+0x3a5/0x4f0 lib/kobject.c:569
 device_move+0xe0/0x700 drivers/base/core.c:4609
 hci_conn_del_sysfs+0xb8/0x170 net/bluetooth/hci_sysfs.c:75
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173
 hci_conn_hash_flush+0x191/0x230 net/bluetooth/hci_conn.c:2561
 hci_dev_do_reset net/bluetooth/hci_core.c:566 [inline]
 hci_dev_reset+0x44b/0x6b0 net/bluetooth/hci_core.c:610
 sock_do_ioctl+0xd9/0x300 net/socket.c:1190
 sock_ioctl+0x576/0x790 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb14858e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb14932a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb1487b5fa0 RCX: 00007fb14858e929
RDX: 0000000000000000 RSI: 00000000400448cb RDI: 0000000000000006
RBP: 00007fb148610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fb1487b5fa0 R15: 00007ffd3f5b1588
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:kernfs_rename_ns+0x3a/0x7a0 fs/kernfs/dir.c:1747
Code: ec 48 48 89 cb 48 89 54 24 10 49 89 f5 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 d1 5b 62 ff 4d 8d 7e 30 4c 89 fd 48 c1 ed 03 <42> 80 7c 25 00 00 74 08 4c 89 ff e8 86 de c5 ff 49 83 3f 00 0f 84
RSP: 0018:ffffc90003ecf9c0 EFLAGS: 00010206
RAX: ffffffff825e02cf RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000cbbb000 RSI: 0000000000000873 RDI: 0000000000000874
RBP: 0000000000000006 R08: ffff88801c7e9e00 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000002 R12: dffffc0000000000
R13: ffff888143acf960 R14: 0000000000000000 R15: 0000000000000030
FS:  00007fb14932a6c0(0000) GS:ffff888125c1d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000002a0fb8 CR3: 000000007d24a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	ec                   	in     (%dx),%al
   1:	48                   	rex.W
   2:	48 89 cb             	mov    %rcx,%rbx
   5:	48 89 54 24 10       	mov    %rdx,0x10(%rsp)
   a:	49 89 f5             	mov    %rsi,%r13
   d:	49 89 fe             	mov    %rdi,%r14
  10:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  17:	fc ff df
  1a:	e8 d1 5b 62 ff       	call   0xff625bf0
  1f:	4d 8d 7e 30          	lea    0x30(%r14),%r15
  23:	4c 89 fd             	mov    %r15,%rbp
  26:	48 c1 ed 03          	shr    $0x3,%rbp
* 2a:	42 80 7c 25 00 00    	cmpb   $0x0,0x0(%rbp,%r12,1) <-- trapping instruction
  30:	74 08                	je     0x3a
  32:	4c 89 ff             	mov    %r15,%rdi
  35:	e8 86 de c5 ff       	call   0xffc5dec0
  3a:	49 83 3f 00          	cmpq   $0x0,(%r15)
  3e:	0f                   	.byte 0xf
  3f:	84                   	.byte 0x84


---
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