qemu-i386-static ioctl return -14 (Bad Address)

This problem has bothered me for a long time, but I'm not sure whether it's the IOCTL () I added or the QEMU with 32 bits. I hope we can discuss it and help our friends who have other problems.

Thank you,my friends!

My environment is that:
schroot + debian(bullseye-i386)
qemu: 5.1.0-rc3

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Hi,I found some problems, but I don't know if how to solve it better(I'm not really familiar with the source code).

When I use ioctl() and use a structure like this:

struct drm_mode_card_res {
        __u64 fb_id_ptr;
        __u64 crtc_id_ptr;
        __u64 connector_id_ptr;
        __u64 encoder_id_ptr;
        __u32 count_fbs;
        ....
};
And in syscall_types.h
STRUCT(drm_mode_card_res,
        TYPE_PTRVOID,
        TYPE_PTRVOID,
        TYPE_PTRVOID,
        TYPE_PTRVOID,
        TYPE_INT,
        ...
        )
Some code:
        ...
 if (res.count_fbs) {
  res.fb_id_ptr = VOID2U64(drmMalloc(res.count_fbs*sizeof(uint32_t)));
  if (!res.fb_id_ptr)
   goto err_allocs;
 }
        ...

This is strace:
openat(AT_FDCWD,"/dev/dri/card0",O_RDWR|O_LARGEFILE|O_CLOEXEC) = 4
9469 ioctl(4,DRM_IOCTL_GET_CAP,{1,0}) = 0 ({1,1})
9469 ioctl(4,DRM_IOCTL_MODE_GETRESOURCES,{0x0,0x0,0x0,0x0,0,0,0,0,0,0,0,0}) = 0 ({0x0,0x0,0x0,0x0,0,2,2,2,0,16384,0,16384})
9469 brk(NULL) = 0x40006000
9469 brk(0x40027000) = 0x40027000
9469 brk(0x40028000) = 0x40028000
9469 ioctl(4,DRM_IOCTL_MODE_GETRESOURCES,{0x0,0x0,0x400061a0,0x0,0,2,1073832368,0,0,16384,0,16384}) = -1 errno=14 (Bad address)
9469 brk(0x40027000) = 0x40027000

Look
9469 ioctl(4,DRM_IOCTL_MODE_GETRESOURCES,{0x0,0x0,0x400061a0,0x0,0,2,1073832368,0,0,16384,0,16384}) = -1 errno=14 (Bad address)

Why does memory overrun occur here???
I think this is right:
{0x0,0x400061a0,1073832368(0x400061a0),0x400061c0,0,2,2,2,0,16384,0,16384}

Who can help me? Thank you!

You need to use IOCTL_SPECIAL() or STRUCT_SPECIAL() macro to convert the target address to the host address.

Again, share your patches on the qemu-devel mailing list if you want help.