[isilence:syz/region-conversion-3 19/20] io_uring/kbuf.c:668:18: error: invalid type argument of '->' (have 'struct io_uring_buf_reg')

[isilence:syz/region-conversion-3 19/20] io_uring/kbuf.c:668:18: error: invalid type argument of '->' (have 'struct io_uring_buf_reg')

[kernel test robot]

tree:   https://github.com/isilence/linux syz/region-conversion-3
head:   eab28eddf62efd7e9a5d20b3b41e5943c9065e90
commit: 6969187115d122af2930e094ba1f6d47594f6953 [19/20] io_uring/kbuf: use region api for pbuf rings
config: parisc-allnoconfig (https://download.01.org/0day-ci/archive/20241126/202411261440.cd8peJRE-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241126/202411261440.cd8peJRE-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202411261440.cd8peJRE-lkp@intel.com/

All errors (new ones prefixed by >>):

   io_uring/kbuf.c: In function 'io_register_pbuf_ring':
>> io_uring/kbuf.c:668:18: error: invalid type argument of '->' (have 'struct io_uring_buf_reg')
     668 |             ((reg->ring_addr | (unsigned long)br) & (SHM_COLOUR - 1))) {
         |                  ^~


vim +668 io_uring/kbuf.c

   606	
   607	int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
   608	{
   609		struct io_uring_buf_reg reg;
   610		struct io_buffer_list *bl, *free_bl = NULL;
   611		struct io_uring_region_desc rd;
   612		struct io_uring_buf_ring *br;
   613		unsigned long mmap_offset;
   614		unsigned long ring_size;
   615		int ret;
   616	
   617		lockdep_assert_held(&ctx->uring_lock);
   618	
   619		if (copy_from_user(&reg, arg, sizeof(reg)))
   620			return -EFAULT;
   621	
   622		if (reg.resv[0] || reg.resv[1] || reg.resv[2])
   623			return -EINVAL;
   624		if (reg.flags & ~(IOU_PBUF_RING_MMAP | IOU_PBUF_RING_INC))
   625			return -EINVAL;
   626		if (!is_power_of_2(reg.ring_entries))
   627			return -EINVAL;
   628		/* cannot disambiguate full vs empty due to head/tail size */
   629		if (reg.ring_entries >= 65536)
   630			return -EINVAL;
   631	
   632		bl = io_buffer_get_list(ctx, reg.bgid);
   633		if (bl) {
   634			/* if mapped buffer ring OR classic exists, don't allow */
   635			if (bl->flags & IOBL_BUF_RING || !list_empty(&bl->buf_list))
   636				return -EEXIST;
   637		} else {
   638			free_bl = bl = kzalloc(sizeof(*bl), GFP_KERNEL);
   639			if (!bl)
   640				return -ENOMEM;
   641		}
   642	
   643		mmap_offset = reg.bgid << IORING_OFF_PBUF_SHIFT;
   644		ring_size = flex_array_size(br, bufs, reg.ring_entries);
   645	
   646		memset(&rd, 0, sizeof(rd));
   647		rd.size = PAGE_ALIGN(ring_size);
   648		if (!(reg.flags & IOU_PBUF_RING_MMAP)) {
   649			rd.user_addr = reg.ring_addr;
   650			rd.flags |= IORING_MEM_REGION_TYPE_USER;
   651		}
   652		ret = io_create_region_mmap_safe(ctx, &bl->region, &rd, mmap_offset);
   653		if (ret)
   654			goto fail;
   655		br = io_region_get_ptr(&bl->region);
   656	
   657	#ifdef SHM_COLOUR
   658		/*
   659		 * On platforms that have specific aliasing requirements, SHM_COLOUR
   660		 * is set and we must guarantee that the kernel and user side align
   661		 * nicely. We cannot do that if IOU_PBUF_RING_MMAP isn't set and
   662		 * the application mmap's the provided ring buffer. Fail the request
   663		 * if we, by chance, don't end up with aligned addresses. The app
   664		 * should use IOU_PBUF_RING_MMAP instead, and liburing will handle
   665		 * this transparently.
   666		 */
   667		if (!(reg.flags & IOU_PBUF_RING_MMAP) &&
 > 668		    ((reg->ring_addr | (unsigned long)br) & (SHM_COLOUR - 1))) {
   669			ret = -EINVAL;
   670			goto fail;
   671		}
   672	#endif
   673	
   674		bl->nr_entries = reg.ring_entries;
   675		bl->mask = reg.ring_entries - 1;
   676		bl->flags |= IOBL_BUF_RING;
   677		bl->buf_ring = br;
   678		if (reg.flags & IOU_PBUF_RING_INC)
   679			bl->flags |= IOBL_INC;
   680		io_buffer_add_list(ctx, bl, reg.bgid);
   681		return 0;
   682	fail:
   683		io_free_region(ctx, &bl->region);
   684		kfree(free_bl);
   685		return ret;
   686	}
   687	

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