Opened 4 months ago

Closed 4 months ago

Last modified 6 weeks ago

#5265 closed defect (fixed)

eudev: specified group 'sgx' unknown

Reported by: ken@… Owned by: ken@…
Priority: normal Milestone: 12.0
Component: Book Version: git
Severity: normal Keywords:


I'm not sure quite what triggers this, but I have various reports in /var/log/syslog of the form:

udevd[203]: specified group 'sgx' unknown

I first noticed this while building BLFS in a tty after I'd used my kvm switch to come back to the machine and saw this on the tty. Now that I've been running a desktop I've got one such entry in the log from a bit over 5 hours ago but that was not at a time when I changed the KVM to or from another machine - there are various usb messages when I do that. My point is that I'm not sure if I can test that the fix will work ;-) However, we clearly do not have the group and have no need of it.

In systemd we change the render group to video and blank out the sgx group in In sysv we do neither, but only sgx is being reported.

/me looks at eudev and systemd:

In systemd the file is rules.d/ but in eudev it is rules/50-udev-default.rules and only the systemd version mentions GROUP="render".

So, not quite the same sed for eudev.

Change History (7)

comment:1 by ken@…, 4 months ago

Owner: changed from lfs-book to ken@…
Status: newassigned

comment:2 by ken@…, 4 months ago

Resolution: fixed
Status: assignedclosed

Fixed 507bf71541 pushed as part of r11.3-98.

comment:3 by Bruce Dubbs, 4 months ago

I took a look at the eudev source and the only place I see 'sgx' is:

rules/50-udev-default.rules:SUBSYSTEM=="misc", KERNEL=="sgx_enclave", GROUP="sgx", MODE="0660"
rules/50-udev-default.rules:SUBSYSTEM=="misc", KERNEL=="sgx_vepc", GROUP="sgx", MODE="0660"

I do not know when or why the sgx_enclave or sgx_vepc are used.

Checking the kernel documentation:

The support can be determined by grep sgx /proc/cpuinfo. I do not have that in either my Intel Workstation or AMD development system. Perhaps that is because my kernel configurations have # CONFIG_X86_SGX is not set.

The kernel configuration says X86_SGX Depends on: X86_64 [=y] && CPU_SUP_INTEL [=y] && X86_X2APIC [=y]...

CONFIG_X86_X2APIC: If you don't know what to do here, say N.

CONFIG_X86_SGX: If unsure, say N.

comment:4 by pierre, 4 months ago

We tell to enable CONFIG_X86_X2APIC on the LFS kernel page...

comment:5 by ken@…, 4 months ago

SGX is described at

A perhaps more detailed description is at - AFAICS you need special hardware (high-end intel servers, I think)

in reply to:  4 comment:6 by Xi Ruoyao, 4 months ago

Replying to pierre:

We tell to enable CONFIG_X86_X2APIC on the LFS kernel page...

Intel says to enable it.

And AFAIK some "if unsure select Y/N" things in kernel configuration help entries are completely outdated.

comment:7 by Bruce Dubbs, 6 weeks ago

Milestone: 11.412.0

Milestone renamed

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