On 5/1/19 9:59 AM, Mark Rutland wrote: > In io_sqe_buffer_register() we allocate a number of arrays based on the > iov_len from the user-provided iov. While we limit iov_len to SZ_1G, > we can still attempt to allocate arrays exceeding MAX_ORDER. > > On a 64-bit system with 4KiB pages, for an iov where iov_base = 0x10 and > iov_len = SZ_1G, we'll calculate that nr_pages = 262145. When we try to > allocate a corresponding array of (16-byte) bio_vecs, requiring 4194320 > bytes, which is greater than 4MiB. This results in SLUB warning that > we're trying to allocate greater than MAX_ORDER, and failing the > allocation. > > Avoid this by using kvmalloc() for allocations dependent on the > user-provided iov_len. At the same time, fix a leak of imu->bvec when > registration fails. Applied, thanks. -- Jens Axboe
