[syzbot] [usb-storage?] general protection fault in alauda_transport

Hello,

syzbot found the following issue on:

HEAD commit:    bdab5605259b usb: gadget: uvc: fix dangling pointers in uv..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=122ed6c6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8bdeea7ee6735f91
dashboard link: https://syzkaller.appspot.com/bug?extid=ccc9a7cb39fa1af827ea
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12012679580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=162ed6c6580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2cb2fdbdd7b7/disk-bdab5605.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f801d31c2001/vmlinux-bdab5605.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9002a6e0ae14/bzImage-bdab5605.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 6317 Comm: usb-storage Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:972 [inline]
RIP: 0010:alauda_transport+0xfd6/0x35c0 drivers/usb/storage/alauda.c:1187
Code: 48 c1 e9 03 80 3c 31 00 0f 85 ee 1d 00 00 48 8b 0b 8b 54 24 10 48 be 00 00 00 00 00 fc ff df 48 8d 1c 51 48 89 d9 48 c1 e9 03 <0f> b6 34 31 48 89 d9 83 e1 07 83 c1 01 40 38 f1 7c 09 40 84 f6 0f
RSP: 0018:ffffc90002dcf9e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff888118ad0920
RBP: 0000000000000240 R08: 0000000000000005 R09: 000000000000001f
R10: 0000000000000009 R11: ffffffff81596b4a R12: 0000000000000001
R13: 0000000000000001 R14: ffff888118ad0900 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888268633000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7516ee1254 CR3: 0000000109f36000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 usb_stor_invoke_transport+0xee/0x15d0 drivers/usb/storage/transport.c:611
 usb_stor_control_thread+0x5e4/0xae0 drivers/usb/storage/usb.c:462
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:972 [inline]
RIP: 0010:alauda_transport+0xfd6/0x35c0 drivers/usb/storage/alauda.c:1187
Code: 48 c1 e9 03 80 3c 31 00 0f 85 ee 1d 00 00 48 8b 0b 8b 54 24 10 48 be 00 00 00 00 00 fc ff df 48 8d 1c 51 48 89 d9 48 c1 e9 03 <0f> b6 34 31 48 89 d9 83 e1 07 83 c1 01 40 38 f1 7c 09 40 84 f6 0f
RSP: 0018:ffffc90002dcf9e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff888118ad0920
RBP: 0000000000000240 R08: 0000000000000005 R09: 000000000000001f
R10: 0000000000000009 R11: ffffffff81596b4a R12: 0000000000000001
R13: 0000000000000001 R14: ffff888118ad0900 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888268733000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb6f8698060 CR3: 0000000125ff4000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
   0:	48 c1 e9 03          	shr    $0x3,%rcx
   4:	80 3c 31 00          	cmpb   $0x0,(%rcx,%rsi,1)
   8:	0f 85 ee 1d 00 00    	jne    0x1dfc
   e:	48 8b 0b             	mov    (%rbx),%rcx
  11:	8b 54 24 10          	mov    0x10(%rsp),%edx
  15:	48 be 00 00 00 00 00 	movabs $0xdffffc0000000000,%rsi
  1c:	fc ff df
  1f:	48 8d 1c 51          	lea    (%rcx,%rdx,2),%rbx
  23:	48 89 d9             	mov    %rbx,%rcx
  26:	48 c1 e9 03          	shr    $0x3,%rcx
* 2a:	0f b6 34 31          	movzbl (%rcx,%rsi,1),%esi <-- trapping instruction
  2e:	48 89 d9             	mov    %rbx,%rcx
  31:	83 e1 07             	and    $0x7,%ecx
  34:	83 c1 01             	add    $0x1,%ecx
  37:	40 38 f1             	cmp    %sil,%cl
  3a:	7c 09                	jl     0x45
  3c:	40 84 f6             	test   %sil,%sil
  3f:	0f                   	.byte 0xf


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