Thread

Re: [PATCH] test_aio: Skip io_uring tests when kernel disables it

Nazir Bilal Yavuz <byavuz81@gmail.com> — 2025-12-10T07:38:05Z

Hi,

On Mon, 8 Dec 2025 at 05:12, Henson Choi <assam258@gmail.com> wrote:
>
> Hi hackers,
>
> I encountered test_aio failures on RHEL 9 / Rocky Linux 9 systems where
> io_uring is disabled by default (io_uring_disabled=2). This is increasingly
> common in enterprise environments.
>
> Background:
> Red Hat disabled io_uring in 2021 and maintains this policy in RHEL 9
> for security reasons. Many critical CVEs have been found (CVE-2021-41073,
> CVE-2022-2602, CVE-2024-0582, etc.), and Google reported that 60% of their
> 2022 kernel exploit submissions targeted io_uring, leading them to disable
> it across Android, ChromeOS, and production servers.
>
> Current behavior:
> The test_aio module only checks if PostgreSQL was compiled with io_uring
> support (have_io_uring) but doesn't check if the kernel allows it.
> This causes test failures on RHEL 9 and similar distributions.
>
> Proposed solution:
> Add io_uring_enabled() to check /proc/sys/kernel/io_uring_disabled.
> Only run io_uring tests when the value is 0 (fully enabled).
>
> Why skip io_uring_disabled=1 (CAP_SYS_ADMIN required) as well:
> - Checking for CAP_SYS_ADMIN capability adds complexity
> - Most test users don't have CAP_SYS_ADMIN
> - High probability of failure, safer to skip
> - Prioritize test simplicity and stability over coverage
>
> Testing:
> - ✓ RHEL 9 (io_uring_disabled=2): Tests skip correctly
> - ✓ Ubuntu 24 (io_uring_disabled=0): Tests run normally
>
> The patch is minimal (adds one function, modifies one condition) and
> follows the existing pattern used for injection points testing.
>
> Thoughts?

Thank you for the report! I am able to reproduce the problem you
mentioned by disabling io_uring with 'sysctl -w
kernel.io_uring_disabled=2' command.

method_io_uring.c has a hint about this problem:

/* add hints for some failures that errno explains sufficiently */
if (-ret == EPERM)
{
    err = ERRCODE_INSUFFICIENT_PRIVILEGE;
    hint = _("Check if io_uring is disabled via
/proc/sys/kernel/io_uring_disabled.");
}

and this hint is shown when you try to set the io_method to io_uring
also this hint is written to the 'regress_log_001_aio' if aio tests
fail because of that. I think it is correct to fail the test and show
the hint when you have an io_uring support but you can not use it
because of some kernel parameters.

-- 
Regards,
Nazir Bilal Yavuz
Microsoft