I've got a server running SL 7.3 and while it has installed many
updates including recent ones under the 7.5 update, it is not
installing all updates to a full SL 7.5 system. I've tried 'yum clean
all' and 'rm -rf /var/cache/yum' and they didn't help. The only clue
is that 'yum check' returned an error, but I don't know if it is
enough to cause yum to just ignore updating seemingly unrelated
packages while allowing others. I would assume that a conflict with a
kmod would block a kernel update but it does not. What other steps can
I do to try to troubleshoot or fix this?

[root@Server log]# yum check
Loaded plugins: fastestmirror
kmod-redhat-mpt3sas-14.101.00.00-1.el7_3.x86_64 has installed
conflicts mpt3sas-kmod:
kmod-redhat-mpt3sas-14.101.00.00-1.el7_3.x86_64
Error: check all

It appears to be stuck at SL 7.3 according to:

[root@Server log]# yum info sl-release
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * epel: mirrors.syringanetworks.net
 * repos: ftp.scientificlinux.org
 * sl: ftp.scientificlinux.org
 * sl-extras: ftp.scientificlinux.org
 * sl-fastbugs: ftp.scientificlinux.org
 * sl-security: ftp.scientificlinux.org
Installed Packages
Name        : sl-release
Arch        : x86_64
Version     : 7.3
Release     : 4.sl7
Size        : 69 k
Repo        : installed
From repo   : sl
Summary     : Scientific Linux release file
License     : GPLv2
Description : Scientific Linux release files

However, it has updated to and is running the kernel for the 7.5 release:

[root@Server log]# uname -a
Linux Server.Company.com 3.10.0-862.6.3.el7.x86_64 #1 SMP Tue Jun 26
12:13:22 CDT 2018 x86_64 x86_64 x86_64 GNU/Linux
[root@Server log]# rpm -qa kernel
kernel-3.10.0-862.6.3.el7.x86_64
kernel-3.10.0-514.21.1.el7.x86_64
kernel-3.10.0-693.11.6.el7.x86_64

Thanks.