I believe the "segfault at" messages are emitted by the kernel when a *userspace* process segfaults (possibly only when it's owned by root or otherwise seems important). If a kernel thread had crashed, I think you'd see an OOPS instead.

kioworker, despite its name, isn't a kernel process. My guess is it's a userspace process associated with the KDE I/O library that handles browsing network filesystems, cloud storage, etc (https://en.wikipedia.org/wiki/KIO). Note too the reference to
the shared library libcxb.so : kernel processes don't use shared libraries.

So you've probably encountered a bug in KIO. I don't think there's any way to guess from this whether it's critical or not. If you're actively using network or cloud filesystems, I can imagine that such a crash could result in corrupted data. I would
take this to KDE people to report and investigate.

On May 16, 2025, at 16:32, Dale <rdalek1967@gmail.com> wrote:

Howdy,

I was looking at messages and ran up on this error. This is on my new
rig, Gentoo-1.

May 16 17:20:16 Gentoo-1 kernel: kioworker[3084]: segfault at 0 ip 00007f95f17510e8 sp 00007ffe1b492d50 error 4 in libxcb.so.1.1.0[7f95f174f000+15000] likely on CPU 15 (core 7, socket 0)
May 16 17:20:16 Gentoo-1 kernel: Code: e8 2d e9 ff ff 66 66 2e 0f 1f 84
00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 41 55 45 89 c6 41 54 55 53
48 83 ec 48 48 8b 19 <8b> 07 89 74 24 18 48 89 4c 24 08 64 48 8b 2c 25
28 00 00 00 48 89
May 16 17:20:17 Gentoo-1 kernel: kioworker[3094]: segfault at 0 ip 00007f792db5b0e8 sp 00007ffe35189c40 error 4 in libxcb.so.1.1.0[7f792db59000+15000] likely on CPU 12 (core 4, socket 0)
May 16 17:20:17 Gentoo-1 kernel: Code: e8 2d e9 ff ff 66 66 2e 0f 1f 84
00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 41 55 45 89 c6 41 54 55 53
48 83 ec 48 48 8b 19 <8b> 07 89 74 24 18 48 89 4c 24 08 64 48 8b 2c 25
28 00 00 00 48 89
May 16 17:20:22 Gentoo-1 kernel: kioworker[3134]: segfault at 0 ip 00007f697b67f0e8 sp 00007ffc70a55dc0 error 4 in libxcb.so.1.1.0[7f697b67d000+15000] likely on CPU 0 (core 0, socket 0)
May 16 17:20:22 Gentoo-1 kernel: Code: e8 2d e9 ff ff 66 66 2e 0f 1f 84
00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 41 55 45 89 c6 41 54 55 53
48 83 ec 48 48 8b 19 <8b> 07 89 74 24 18 48 89 4c 24 08 64 48 8b 2c 25
28 00 00 00 48 89
May 16 17:20:32 Gentoo-1 kernel: kioworker[3260]: segfault at 0 ip 00007f1673a630e8 sp 00007fff16070d80 error 4 in libxcb.so.1.1.0[7f1673a61000+15000] likely on CPU 1 (core 1, socket 0)
May 16 17:20:32 Gentoo-1 kernel: Code: e8 2d e9 ff ff 66 66 2e 0f 1f 84
00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 41 55 45 89 c6 41 54 55 53
48 83 ec 48 48 8b 19 <8b> 07 89 74 24 18 48 89 4c 24 08 64 48 8b 2c 25
28 00 00 00 48 89
May 16 17:20:46 Gentoo-1 kernel: kioworker[3368]: segfault at 0 ip 00007f137ace60e8 sp 00007ffd5b05ace0 error 4 in libxcb.so.1.1.0[7f137ace4000+15000] likely on CPU 9 (core 1, socket 0)
May 16 17:20:46 Gentoo-1 kernel: Code: e8 2d e9 ff ff 66 66 2e 0f 1f 84
00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 41 55 45 89 c6 41 54 55 53
48 83 ec 48 48 8b 19 <8b> 07 89 74 24 18 48 89 4c 24 08 64 48 8b 2c 25
28 00 00 00 48 89
May 16 17:20:49 Gentoo-1 kernel: kioworker[3388]: segfault at 0 ip 00007f0849f650e8 sp 00007fff5b6ab990 error 4 in libxcb.so.1.1.0[7f0849f63000+15000] likely on CPU 6 (core 6, socket 0)
May 16 17:20:49 Gentoo-1 kernel: Code: e8 2d e9 ff ff 66 66 2e 0f 1f 84
00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 41 55 45 89 c6 41 54 55 53
48 83 ec 48 48 8b 19 <8b> 07 89 74 24 18 48 89 4c 24 08 64 48 8b 2c 25
28 00 00 00 48 89
May 16 17:20:59 Gentoo-1 kernel: kioworker[3507]: segfault at 0 ip 00007f004dee50e8 sp 00007ffcaad409b0 error 4 in libxcb.so.1.1.0[7f004dee3000+15000] likely on CPU 6 (core 6, socket 0)
May 16 17:20:59 Gentoo-1 kernel: Code: e8 2d e9 ff ff 66 66 2e 0f 1f 84
00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 41 55 45 89 c6 41 54 55 53
48 83 ec 48 48 8b 19 <8b> 07 89 74 24 18 48 89 4c 24 08 64 48 8b 2c 25
28 00 00 00 48 89
May 16 17:21:07 Gentoo-1 kernel: kioworker[3577]: segfault at 0 ip 00007f08b90c50e8 sp 00007ffebba62ee0 error 4 in libxcb.so.1.1.0[7f08b90c3000+15000] likely on CPU 13 (core 5, socket 0)
May 16 17:21:07 Gentoo-1 kernel: Code: e8 2d e9 ff ff 66 66 2e 0f 1f 84
00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 41 55 45 89 c6 41 54 55 53
48 83 ec 48 48 8b 19 <8b> 07 89 74 24 18 48 89 4c 24 08 64 48 8b 2c 25
28 00 00 00 48 89

Everything seems to be working fine. Is this a kernel bug, error or is
it something else? Do I need to treat this as serious or is it no big
deal? It only pops up every once in a while. It's not something that happens all the time. It does it, stops and then later on another set.
Not always the same CPU numbers either. That is the complete set for
this time. I think kioworker is a kernel process. I'm on
gentoo-sources and this is uname -r. 6.9.10-gentoo

Thoughts?

Dale

:-) :-)

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