Re: [PATCH 1/1] io_uring: sanitise nr_pages for SQ/CQ

Pavel Begunkov <asml.silence@xxxxxxxxx> · Mon, 25 Nov 2024 23:44:33 +0000

On 11/25/24 23:22, Pavel Begunkov wrote:
WARNING: CPU: 0 PID: 5834 at io_uring/memmap.c:144 io_pin_pages+0x149/0x180 io_uring/memmap.c:144
CPU: 0 UID: 0 PID: 5834 Comm: syz-executor825 Not tainted 6.12.0-next-20241118-syzkaller #0
Call Trace:
  <TASK>
  __io_uaddr_map+0xfb/0x2d0 io_uring/memmap.c:183
  io_rings_map io_uring/io_uring.c:2611 [inline]
  io_allocate_scq_urings+0x1c0/0x650 io_uring/io_uring.c:3470
  io_uring_create+0x5b5/0xc00 io_uring/io_uring.c:3692
  io_uring_setup io_uring/io_uring.c:3781 [inline]
  ...
  </TASK>

Apparently there is a way to request a large enough CQ/SQ so that the
number of pages used doesn't fit into int. Even worse, then it's
truncated further to ushort. Limit them to the type size for now, but
it needs a better follow up.

Nevermind, syz says it doesn't fix it.

--
Pavel Begunkov