Re: [syzbot] [usb?] general protection fault in uvcg_video_enable

syzbot has found a reproducer for the following issue on:

HEAD commit:    d58772d8520c Merge tag 'regmap-fix-v7.2-rc7' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1434a879580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d07fbc6821d72a61
dashboard link: https://syzkaller.appspot.com/bug?extid=44835f0858f11e3e923c
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17d69879580000

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

audit: backlog limit exceeded
configfs-gadget.g1 gadget.32: uvc: uvc_function_bind()
use of bytesused == 0 is deprecated and will be removed in the future,
use the actual size instead.
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 2 UID: 0 PID: 6048 Comm: syz-executor268 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:usb_endpoint_xfer_isoc include/uapi/linux/usb/ch9.h:571 [inline]
RIP: 0010:uvc_video_prep_requests drivers/usb/gadget/function/uvc_video.c:508 [inline]
RIP: 0010:uvc_video_alloc_requests drivers/usb/gadget/function/uvc_video.c:559 [inline]
RIP: 0010:uvcg_video_enable+0x12d/0xf80 drivers/usb/gadget/function/uvc_video.c:784
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b7 0d 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 18 48 8d 7d 03 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 e5 0d 00 00
RSP: 0018:ffffc900033a7b58 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff88802e74c100 RCX: ffffffff87e608b8
RDX: 0000000000000000 RSI: ffffffff87e608c5 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: ffff88802c31e8f0 R15: ffff88802c31e840
FS:  000055555baac400(0000) GS:ffff8880d5dd7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555bab0000 CR3: 000000003df62000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 uvc_v4l2_streamon+0x9f/0x130 drivers/usb/gadget/function/uvc_v4l2.c:531
 __video_do_ioctl+0xb2a/0xdf0 drivers/media/v4l2-core/v4l2-ioctl.c:3133
 video_usercopy+0x47a/0x1730 drivers/media/v4l2-core/v4l2-ioctl.c:3475
 v4l2_ioctl+0x1bd/0x250 drivers/media/v4l2-core/v4l2-dev.c:366
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc0f28ab40b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007fffe9a50160 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fffe9a501e8 RCX: 00007fc0f28ab40b
RDX: 00007fffe9a501e0 RSI: 0000000040045612 RDI: 0000000000000003
RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000008000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fffe9a501e0 R14: 00000000c0585609 R15: 00000000c058560f
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:usb_endpoint_xfer_isoc include/uapi/linux/usb/ch9.h:571 [inline]
RIP: 0010:uvc_video_prep_requests drivers/usb/gadget/function/uvc_video.c:508 [inline]
RIP: 0010:uvc_video_alloc_requests drivers/usb/gadget/function/uvc_video.c:559 [inline]
RIP: 0010:uvcg_video_enable+0x12d/0xf80 drivers/usb/gadget/function/uvc_video.c:784
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b7 0d 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 18 48 8d 7d 03 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 e5 0d 00 00
RSP: 0018:ffffc900033a7b58 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff88802e74c100 RCX: ffffffff87e608b8
RDX: 0000000000000000 RSI: ffffffff87e608c5 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: ffff88802c31e8f0 R15: ffff88802c31e840
FS:  000055555baac400(0000) GS:ffff8880d5cd7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055703341ef30 CR3: 000000003df62000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	48 89 fa             	mov    %rdi,%rdx
   3:	48 c1 ea 03          	shr    $0x3,%rdx
   7:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   b:	0f 85 b7 0d 00 00    	jne    0xdc8
  11:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  18:	fc ff df
  1b:	48 8b 6b 18          	mov    0x18(%rbx),%rbp
  1f:	48 8d 7d 03          	lea    0x3(%rbp),%rdi
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2e:	48 89 fa             	mov    %rdi,%rdx
  31:	83 e2 07             	and    $0x7,%edx
  34:	38 d0                	cmp    %dl,%al
  36:	7f 08                	jg     0x40
  38:	84 c0                	test   %al,%al
  3a:	0f 85 e5 0d 00 00    	jne    0xe25


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