[syzbot] [kernel?] BUG: unable to handle kernel paging request in netdev_unregister_kobject (2)

[syzbot] [kernel?] BUG: unable to handle kernel paging request in netdev_unregister_kobject (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    21d6ac051080 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=10ceee79580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d1128bc53f2ef7f3
dashboard link: https://syzkaller.appspot.com/bug?extid=be6bbcdae3e70335dfa2
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/88380e2ddcb9/disk-21d6ac05.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5dba5c2896b7/vmlinux-21d6ac05.xz
kernel image: https://storage.googleapis.com/syzbot-assets/52ac739e37e0/Image-21d6ac05.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+be6bbcdae3e70335dfa2@syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address dfff80000000000b
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0
[dfff80000000000b] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 8158 Comm: kbnepd bnep0 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : klist_put+0x50/0x11c lib/klist.c:212
lr : klist_put+0x2c/0x11c lib/klist.c:210
sp : ffff8000939e7800
x29: ffff8000939e7800 x28: 1fffe0001a7819c2 x27: ffff0000d3c0c008
x26: 1fffe0001a781805 x25: dfff800000000000 x24: 1fffe0001e9b428c
x23: dfff800000000000 x22: ffff0000d3c0c800 x21: 0000000000000001
x20: 0000000000000000 x19: ffff0000f4da1460 x18: 0000000000000000
x17: ffff800084d7fe14 x16: ffff8000824e8a44 x15: ffff80008251a5d0
x14: ffff800080f08a9c x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: ffff60001e5d5ab5 x9 : 0000000000000000
x8 : 000000000000000b x7 : 0000000000000000 x6 : ffff800080b95428
x5 : ffff0000c9f78710 x4 : 0000000000000008 x3 : ffff800080ef89ec
x2 : 0000000000000001 x1 : ffff0000cfd33a80 x0 : 0000000000000000
Call trace:
 klist_put+0x50/0x11c lib/klist.c:212 (P)
 klist_del+0x24/0x34 lib/klist.c:230
 device_del+0x188/0x71c drivers/base/core.c:3938
 netdev_unregister_kobject+0x2a8/0x39c net/core/net-sysfs.c:2308
 unregister_netdevice_many_notify+0x123c/0x1760 net/core/dev.c:12481
 unregister_netdevice_many net/core/dev.c:12509 [inline]
 unregister_netdevice_queue+0x274/0x30c net/core/dev.c:12320
 unregister_netdevice include/linux/netdevice.h:3474 [inline]
 unregister_netdev+0x2c/0x70 net/core/dev.c:12527
 bnep_session+0x21b8/0x239c net/bluetooth/bnep/core.c:544
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
Code: f9400268 927ff914 91016288 d343fd08 (38776908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	f9400268 	ldr	x8, [x19]
   4:	927ff914 	and	x20, x8, #0xfffffffffffffffe
   8:	91016288 	add	x8, x20, #0x58
   c:	d343fd08 	lsr	x8, x8, #3
* 10:	38776908 	ldrb	w8, [x8, x23] <-- trapping instruction


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