create_posix_buf(umode_t mode)
{
	struct create_posix *buf;

	buf = kzalloc(sizeof(struct create_posix),
			GFP_KERNEL);
	if (!buf)
		return NULL;

	buf->ccontext.DataOffset =
		cpu_to_le16(offsetof(struct create_posix, Mode));
	buf->ccontext.DataLength = cpu_to_le32(4);
	buf->ccontext.NameOffset =
		cpu_to_le16(offsetof(struct create_posix, Name));
	buf->ccontext.NameLength = cpu_to_le16(16);

	/* SMB2_CREATE_TAG_POSIX is "0x93AD25509CB411E7B42383DE968BCD7C" */
	buf->Name[0] = 0x93;
	buf->Name[1] = 0xAD;
	buf->Name[2] = 0x25;
	buf->Name[3] = 0x50;
	buf->Name[4] = 0x9C;
	buf->Name[5] = 0xB4;
	buf->Name[6] = 0x11;
	buf->Name[7] = 0xE7;
	buf->Name[8] = 0xB4;
	buf->Name[9] = 0x23;
	buf->Name[10] = 0x83;
	buf->Name[11] = 0xDE;
	buf->Name[12] = 0x96;
	buf->Name[13] = 0x8B;
	buf->Name[14] = 0xCD;
	buf->Name[15] = 0x7C;
	buf->Mode = cpu_to_le32(mode);
	cifs_dbg(FYI, "mode on posix create 0%o", mode);
	return buf;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.