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I've updated my fedora linux with dnf update to kernel version Linux 5.16.7-200.fc35.x86_64 x86_64 and am now getting a EPERM/permission denied error for a call to io_uring_queue_init, even when calling my program as root.

I am at a total loss, is this a bug in the kernel build or do I need to add some init code?

Klemens Morgenstern
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  • What version was the kernel before the update and what flags are given to `io_uring_queue_init`? – user17732522 Feb 11 '22 at 04:33
  • I don't remember the version before, because I did only notice a few days after updating. I am using io_uring through asio, so that's the init code: https://github.com/chriskohlhoff/asio/blob/51d5bb3d493f82446e525f68d5b79002e1d797d2/asio/include/asio/detail/impl/io_uring_service.ipp#L511 – Klemens Morgenstern Feb 11 '22 at 04:40
  • just wanted to play around io_uring as well today, but I have the same issue with `5.16.5-200.fc35.x86_64`. – Thomas Jungblut Feb 11 '22 at 14:06
  • Maybe `strace` the io_uring syscalls and add the result to the question to determine the right direction to look for the cause. – user17732522 Feb 11 '22 at 17:11

1 Answers1

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It was selinux, I solved it by disabling selinux.

The upgrade came with kernel 5.16:

https://www.phoronix.com/scan.php?page=news_item&px=SELinux-IO_uring-Linux-5.16

Klemens Morgenstern
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