general protection fault in alauda_transport

Status: upstream: reported C repro on 2026/08/21 07:30
Subsystems: usb-storage
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+ccc9a7cb39fa1af827ea@syzkaller.appspotmail.com
First crash: 4d18h, last: 4d16h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
5a27b9cb assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ general protection fault in alauda_transport 2026/08/18 00:46 2026/08/18 00:46 2026/08/18 01:23 1e72964b
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [usb-storage?] general protection fault in alauda_transport 0 (1) 2026/08/21 07:30

Sample crash report:
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

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/17 08:59 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 746171ee .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-usb general protection fault in alauda_transport
2026/08/17 07:21 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb general protection fault in alauda_transport
* Struck through repros no longer work on HEAD.