Samba service does not start after kernel update

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clark_gable
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Joined: 2022/08/19 12:50:49

Samba service does not start after kernel update

Post by clark_gable » 2022/08/19 13:10:24

Hello,
I have Samba services running as a file server as a virtual machine on several ESX servers. After I restarted the server after a long time, the Samba service stopped running because there were always problems with GNUTLS. After tests I can now say that the problem can be fixed just by selecting the "right" kernel at startup. This article put me on the right track: https://stackoverflow.com/questions/656 ... n-centos-8

If the command
cat /proc/cpuinfo | grep xsave
does not return a result, Samba will not start. If on the other hand the xsave flag is found, starting Samba is no problem.

I have tested these kernels:
OK -> kernel-4.18.0-305.10.2.el8_4.x86_64
OK -> kernel-4.18.0-331.el8.x86_64
NOK -> kernel-4.18.0-383.el8.x86_64
NOK -> kernel-4.18.0-394.el8.x86_64
NOK -> kernel-4.18.0-408.el8.x86_64

My CPU:
Intel(R) Xeon(R) Silver 4208 CPU @ 2.10GHz

My virtualization: ESXi 7.0

/var/log/messages
Aug 18 19:15:56 samba01vo kernel: traps: net[6284] trap invalid opcode ip:7fed5e69178a sp:7ffe65e63480 error:0 in libgnutls.so.30.28.2[7fed5e54c000+1dd000]
Aug 18 19:15:56 samba01vo systemd[1]: Started Process Core Dump (PID 6286/UID 0).
Aug 18 19:15:57 samba01vo systemd-coredump[6287]: Resource limits disable core dumping for process 6284 (net).
Aug 18 19:15:57 samba01vo systemd-coredump[6287]: Process 6284 (net) of user 0 dumped core.
Aug 18 19:15:57 samba01vo systemd[1]: systemd-coredump@2-6286-0.service: Succeeded.
Aug 18 19:21:28 samba01vo systemd[1]: Starting Cleanup of Temporary Directories....
Aug 18 19:21:28 samba01vo systemd[1]: systemd-tmpfiles-clean.service: Succeeded.
Aug 18 19:21:28 samba01vo systemd[1]: Started Cleanup of Temporary Directories.
Aug 18 19:28:48 samba01vo systemd[1]: session-3.scope: Succeeded.

The installation is a pure CentOS Stream 8 installation without any other repos. What do I have to do to make the kernels work again in the future with samba and especially with GNUTLS?

Greetings

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TrevorH
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Re: Samba service does not start after kernel update

Post by TrevorH » 2022/08/19 13:40:55

Make sure that all packages are up to date, do not cherry pick updates. They are tested as a batch not individually.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

clark_gable
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Joined: 2022/08/19 12:50:49

Re: Samba service does not start after kernel update

Post by clark_gable » 2022/08/19 13:59:25

There is a completely new Minimal installation updated, Samba installed and configured. Also a join to the domain only works with matching kernel.

Install different kernel versions and reboot and test. Only the different versions of the kernels were installed or deleted during the tests:
kernel-4.18.0-???.el8.x86_64
kernel-core-4.18.0-???.el8.x86_64
kernel-modules-4.18.0-???.el8.x86_64

No other changes were made during the testing phase.

BShT
Posts: 584
Joined: 2019/10/09 12:31:40

Re: Samba service does not start after kernel update

Post by BShT » 2022/08/19 15:03:41

do not use stream as production

use an enterprise distro

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TrevorH
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Re: Samba service does not start after kernel update

Post by TrevorH » 2022/08/19 15:20:25

Only the different versions of the kernels were installed or deleted during the tests
That appears to say exactly the opposite of what I suggested and that you only updated the kernels. You must perform all updates, not cherry pick the ones you think you want.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

clark_gable
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Joined: 2022/08/19 12:50:49

Re: Samba service does not start after kernel update

Post by clark_gable » 2022/08/23 07:49:10

I have been using CentOS since version 4. I have installed all updates with dnf-automatic. I just wanted to point out that I found a problem with the new kernel in conjunction with Samba and possibly with ESXi.

My intention was and is to improve something by reporting this problem. I therefore wrote the ticket after I knew where my problem comes from.

So for me and my systems I find a way to work around the problem. I am only of the opinion that one can achieve more together than if only everyone fights for himself.

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jlehtone
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Re: Samba service does not start after kernel update

Post by jlehtone » 2022/08/24 07:52:13

clark_gable wrote:
2022/08/19 13:10:24
If the command
cat /proc/cpuinfo | grep xsave
does not return a result, Samba will not start. If on the other hand the xsave flag is found, starting Samba is no problem.
The thread that you linked to did note that if CPU has fma, then it must also have xsave, or some binary selects execution path that will fail.
That is, if only the first of these returns text, then that binary fails:

Code: Select all

grep -m 1 -E "fma|xsave" /proc/cpuinfo
grep -m1 fma /proc/cpuinfo | grep xsave
That thread is old though, so should not be about recent Stream 8's kernels. Besides, it would be an ESX issue, if it allows flag combinations that no physical CPU has.


You write that GNUTLS has issues. Samba does not do that itself, it calls gnutls. In RHEL 8 that is gnutls-0:3.6.16-4.el8. Apparently, Stream 8 has that same version.

Is it possible that latest Stream kernels have new, backported feature that is not "complete"? Yes, even RHEL 8.6 was allegedly released with such kernel.

Which packages would detect the feature and fail to use it due? Samba is probably collateral casualty, if real issue is between kernel and gnutls.

Does this issue occur only on peculiar set of CPU features?

Is it important to report Stream bugs and regressions? Yes, nobody wants to find them from RHEL.

Where does one report Stream bugs? Not on this forum. See https://wiki.centos.org/ReportBugs

clark_gable
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Joined: 2022/08/19 12:50:49

Re: Samba service does not start after kernel update

Post by clark_gable » 2022/10/05 09:42:14

After an ESX update, I no longer have the problems.

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