[syzbot] [usb?] general protection fault in dummy_set_selfpowered

Hello,

syzbot found the following issue on:

HEAD commit:    f5098b6bae76 Linux 7.2-rc5
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=101426b9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cb17729fb04b1e3a
dashboard link: https://syzkaller.appspot.com/bug?extid=5c0303816c30d2e621df
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14dc67b1580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11b89632580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/af1f735fe999/disk-f5098b6b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a9ba72031565/vmlinux-f5098b6b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5bfbc9338ea7/bzImage-f5098b6b.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: 1 UID: 0 PID: 5939 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:dummy_set_selfpowered+0xbe/0x160 drivers/usb/gadget/udc/dummy_hcd.c:906
Code: 8d 34 c6 49 81 c6 c8 07 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 fc 22 01 fb 4d 8b 3e 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 e3 22 01 fb 41 be 00 14 00 00 4d
RSP: 0018:ffffc90003aaf780 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88803c6e0000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff872e19b0 R12: dffffc0000000000
R13: ffff88803ab92528 R14: ffff88802a2fd408 R15: 0000000000000000
FS:  00005555757b0500(0000) GS:ffff888125d41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000004417e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 usb_gadget_set_selfpowered+0x75/0x260 drivers/usb/gadget/udc/core.c:578
 composite_dev_prepare+0x2fa/0x320 drivers/usb/gadget/composite.c:2440
 configfs_composite_bind+0xa5/0x1410 drivers/usb/gadget/configfs.c:1701
 gadget_bind_driver+0x2ca/0x9e0 drivers/usb/gadget/udc/core.c:1662
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
 __driver_attach+0x339/0x600 drivers/base/dd.c:1292
 bus_for_each_dev+0x23e/0x2c0 drivers/base/bus.c:383
 bus_add_driver+0x348/0x670 drivers/base/bus.c:763
 driver_register+0x23a/0x320 drivers/base/driver.c:174
 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752
 gadget_dev_desc_UDC_store+0x1c9/0x2f0 drivers/usb/gadget/configfs.c:300
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x33a/0x430 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61e/0xbb0 fs/read_write.c:687
 ksys_write+0x156/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5cd9f1de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc750c2c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5cda1a5fa0 RCX: 00007f5cd9f1de99
RDX: 000000000000000c RSI: 0000200000001100 RDI: 0000000000000003
RBP: 00007f5cd9fb3eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5cda1a5fac R14: 00007f5cda1a5fa0 R15: 00007f5cda1a5fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dummy_set_selfpowered+0xbe/0x160 drivers/usb/gadget/udc/dummy_hcd.c:906
Code: 8d 34 c6 49 81 c6 c8 07 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 fc 22 01 fb 4d 8b 3e 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 e3 22 01 fb 41 be 00 14 00 00 4d
RSP: 0018:ffffc90003aaf780 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88803c6e0000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff872e19b0 R12: dffffc0000000000
R13: ffff88803ab92528 R14: ffff88802a2fd408 R15: 0000000000000000
FS:  00005555757b0500(0000) GS:ffff888125d41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000004417e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	8d 34 c6             	lea    (%rsi,%rax,8),%esi
   3:	49 81 c6 c8 07 00 00 	add    $0x7c8,%r14
   a:	4c 89 f0             	mov    %r14,%rax
   d:	48 c1 e8 03          	shr    $0x3,%rax
  11:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
  16:	74 08                	je     0x20
  18:	4c 89 f7             	mov    %r14,%rdi
  1b:	e8 fc 22 01 fb       	call   0xfb01231c
  20:	4d 8b 3e             	mov    (%r14),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ff             	mov    %r15,%rdi
  34:	e8 e3 22 01 fb       	call   0xfb01231c
  39:	41 be 00 14 00 00    	mov    $0x1400,%r14d
  3f:	4d                   	rex.WRB


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