[syzbot] [usb-storage?] divide error in alauda_transport

[syzbot] [usb-storage?] divide error in alauda_transport

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7f063b2f17ea Merge tag 'for_linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13d23e79580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=202110c0ee6856a6
dashboard link: https://syzkaller.appspot.com/bug?extid=dc208a8cf8d37cf3e5ac
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: i386
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16c3e549580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8ee85add2a67/disk-7f063b2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d02bce810bb/vmlinux-7f063b2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/12151938fa51/bzImage-7f063b2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dc208a8cf8d37cf3e5ac@syzkaller.appspotmail.com

Oops: divide error: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 5915 Comm: usb-storage Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:954 [inline]
RIP: 0010:alauda_transport+0xbd6/0x43a0 drivers/usb/storage/alauda.c:1187
Code: 24 70 e8 2d e9 2e fa 41 0f b7 c4 0f b7 cb 89 8c 24 e0 00 00 00 48 8b 5c 24 40 4c 8b 74 24 28 45 89 fc 41 89 c7 44 89 f8 31 d2 <f7> b4 24 e8 00 00 00 89 54 24 50 41 89 c5 48 89 df 89 c6 e8 52 61
RSP: 0018:ffffc9000249f860 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88807ff3ce90 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc9000249faf0 R08: ffff888026289f40 R09: 0000000000000004
R10: 00000000ffffffe0 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffff88807ff3d258 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125014000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f67dcda4 CR3: 0000000070670000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 usb_stor_invoke_transport+0x115/0x1a40 drivers/usb/storage/transport.c:611
 usb_stor_control_thread+0x44c/0x8f0 drivers/usb/storage/usb.c:462
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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:954 [inline]
RIP: 0010:alauda_transport+0xbd6/0x43a0 drivers/usb/storage/alauda.c:1187
Code: 24 70 e8 2d e9 2e fa 41 0f b7 c4 0f b7 cb 89 8c 24 e0 00 00 00 48 8b 5c 24 40 4c 8b 74 24 28 45 89 fc 41 89 c7 44 89 f8 31 d2 <f7> b4 24 e8 00 00 00 89 54 24 50 41 89 c5 48 89 df 89 c6 e8 52 61
RSP: 0018:ffffc9000249f860 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88807ff3ce90 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc9000249faf0 R08: ffff888026289f40 R09: 0000000000000004
R10: 00000000ffffffe0 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffff88807ff3d258 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124f14000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1b845212c0 CR3: 0000000072220000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	24 70                	and    $0x70,%al
   2:	e8 2d e9 2e fa       	call   0xfa2ee934
   7:	41 0f b7 c4          	movzwl %r12w,%eax
   b:	0f b7 cb             	movzwl %bx,%ecx
   e:	89 8c 24 e0 00 00 00 	mov    %ecx,0xe0(%rsp)
  15:	48 8b 5c 24 40       	mov    0x40(%rsp),%rbx
  1a:	4c 8b 74 24 28       	mov    0x28(%rsp),%r14
  1f:	45 89 fc             	mov    %r15d,%r12d
  22:	41 89 c7             	mov    %eax,%r15d
  25:	44 89 f8             	mov    %r15d,%eax
  28:	31 d2                	xor    %edx,%edx
* 2a:	f7 b4 24 e8 00 00 00 	divl   0xe8(%rsp) <-- trapping instruction
  31:	89 54 24 50          	mov    %edx,0x50(%rsp)
  35:	41 89 c5             	mov    %eax,%r13d
  38:	48 89 df             	mov    %rbx,%rdi
  3b:	89 c6                	mov    %eax,%esi
  3d:	e8                   	.byte 0xe8
  3e:	52                   	push   %rdx
  3f:	61                   	(bad)


---
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