[v6.6] general protection fault in bnep_session (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: da47cbc25466 Linux 6.6.144
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13fb9d46580000
kernel config: https://syzkaller.appspot.com/x/.config?x=938110aa66424b94
dashboard link: https://syzkaller.appspot.com/bug?extid=9b41ebdb68f89a05ddc8
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a9e82134d7e6/disk-da47cbc2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/296a86743157/vmlinux-da47cbc2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c5adb532f254/bzImage-da47cbc2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9b41eb...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
CPU: 1 PID: 6373 Comm: kbnepd bnep0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:klist_put lib/klist.c:212 [inline]
RIP: 0010:klist_del+0x49/0x110 lib/klist.c:230
Code: 0f f7 49 89 dc 49 c1 ec 03 43 80 3c 3c 00 74 08 48 89 df e8 d9 f2 67 f7 4c 8b 33 49 83 e6 fe 49 8d 7e 58 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 74 05 e8 bb f2 67 f7 49 8b 46 58 48 89 04 24 4c 89
RSP: 0018:ffffc9000c1778e0 EFLAGS: 00010202
RAX: 000000000000000b RBX: ffff888022c3d460 RCX: ffff88801becda00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000058
RBP: ffffc9000c177a10 R08: ffff8880260e17c3 R09: 1ffff11004c1c2f8
R10: dffffc0000000000 R11: ffffed1004c1c2f9 R12: 1ffff11004587a8c
R13: 0000000000000001 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000238030 CR3: 00000000605df000 CR4: 00000000003506e0
Call Trace:
<TASK>
device_del+0x280/0x910 drivers/base/core.c:3866
unregister_netdevice_many_notify+0x1449/0x1910 net/core/dev.c:11154
unregister_netdevice_many net/core/dev.c:11180 [inline]
unregister_netdevice_queue net/core/dev.c:11060 [inline]
unregister_netdevice include/linux/netdevice.h:3137 [inline]
unregister_netdev+0x150/0x1c0 net/core/dev.c:11198
bnep_session+0x29a4/0x2b90 net/bluetooth/bnep/core.c:547
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:klist_put lib/klist.c:212 [inline]
RIP: 0010:klist_del+0x49/0x110 lib/klist.c:230
Code: 0f f7 49 89 dc 49 c1 ec 03 43 80 3c 3c 00 74 08 48 89 df e8 d9 f2 67 f7 4c 8b 33 49 83 e6 fe 49 8d 7e 58 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 74 05 e8 bb f2 67 f7 49 8b 46 58 48 89 04 24 4c 89
RSP: 0018:ffffc9000c1778e0 EFLAGS: 00010202
RAX: 000000000000000b RBX: ffff888022c3d460 RCX: ffff88801becda00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000058
RBP: ffffc9000c177a10 R08: ffff8880260e17c3 R09: 1ffff11004c1c2f8
R10: dffffc0000000000 R11: ffffed1004c1c2f9 R12: 1ffff11004587a8c
R13: 0000000000000001 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000238030 CR3: 00000000605df000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
0: 0f maskmovq (bad),%mm1
1: f7 49 89 dc 49 c1 ec testl $0xecc149dc,-0x77(%rcx)
8: 03 43 80 add -0x80(%rbx),%eax
b: 3c 3c cmp $0x3c,%al
d: 00 74 08 48 add %dh,0x48(%rax,%rcx,1)
11: 89 df mov %ebx,%edi
13: e8 d9 f2 67 f7 call 0xf767f2f1
18: 4c 8b 33 mov (%rbx),%r14
1b: 49 83 e6 fe and $0xfffffffffffffffe,%r14
1f: 49 8d 7e 58 lea 0x58(%r14),%rdi
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction
2f: 74 05 je 0x36
31: e8 bb f2 67 f7 call 0xf767f2f1
36: 49 8b 46 58 mov 0x58(%r14),%rax
3a: 48 89 04 24 mov %rax,(%rsp)
3e: 4c rex.WR
3f: 89 .byte 0x89


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