lkml.org 
[lkml]   [2019]   [May]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCHv2] io_uring: avoid page allocation warnings
From
Date
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

\
 
 \ /
  Last update: 2019-05-01 18:01    [W:0.035 / U:0.128 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site