Well, you found a bug here. lo_simple_ioctl(LOOP_SET_BLOCK_SIZE) passes "unsigned long arg" to loop_validate_block_size() via loop_set_block_size(), and uses only lower 32bits. "(lo->lo_queue->limits.logical_block_size == arg)" is failing to "return 0;" if lower 32bits are the same but higher 32bits are not 0. Shouldn't we also check that higher 32bits are 0, by either making loop_validate_block_size() to accept "unsigned long" or making loop_set_block_size() return -EINVAL if larger than UINT_MAX ? > There is nothing wrong here, so just shut up the check by changing > the type of the bsize argument. I think there is something wrong here. Since "unsigned short bsize" checked only lower 16bits, a fuzzer can pass e.g. 0xDEAD0200 (which is not a is_power_of_2() 32bits value) to blk_queue_logical_block_size(lo->lo_queue, arg); blk_queue_physical_block_size(lo->lo_queue, arg); blk_queue_io_min(lo->lo_queue, arg); and confuse the system?
