NFS client issues after upgrade to kernel 5.14.21-150400.24.49.3

SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server for SAP Applications 15 SP4

Kernel 5.14.21-150400.24.49.3 was installed.  When the system loads this new kernel, NFSv4 client mounts may show question marks where permissions, ownership and other file metadata is expected.  Creating, deleting, and renaming files may not work as expected until the share is unmounted and remounted.

Upgrade to a newer kernel (5.14.21-150400.24.55.3 or newer).  The ...49.3 kernel introduced an NFS bug.  It was retracted from the update repository but a few systems may have received the update while it was available.

Impacted kernel (5.14.21-150400.24.49.3) is listed as retracted on our official kernel list TID here:

https://www.suse.com/support/kb/doc/?id=000019587

More info can be found in this publicly-accessible bug report logged against openSUSE 15.4.

https://bugzilla.suse.com/show_bug.cgi?id=1209457

Before a newer replacement kernel was available, instructions were provided (previously in the Resolution section, above) to clean out the offending kernel and return to the previous version.  Those instructions are preserved below in case they are still wanted.  However, updating to a newer kernel is now the preferred solution.

Old solution:

Downgrade to kernel 5.14.21-150400.24.46.1.  Then clean out the old kernel and boot options via zypper and grub.  Steps to accomplish this:

Step 1: Downgrade to the last unaffected kernel:

# zypper in --oldpackage kernel-default-5.14.21-150400.24.46.1

Step 2: Comment out the current multiversion.kernels entry used by zypp.conf:

# sed -i 's/multiversion.kernels/#multiversion.kernels/' /etc/zypp/zypp.conf

Step 3: Append the known working kernel version to the end of the file.  The version set here is matched against the filename in /boot when zypper purge-kernels is called.  The following command actually adds two lines, the first being a comment:

# echo -e "# line below added per TID000021021\nmultiversion.kernels = 5.14.21-150400.24.46" >> /etc/zypp/zypp.conf

Step 4: Purge kernels (which will clean out all but the desired .46 kernel).

# zypper purge-kernels

Step 5: Regenerate GRUB2 configuration:

# grub2-mkconfig -o /boot/grub2/grub.cfg

Step 6: Manually check /boot directory to make sure kernel 5.14.21-150400.24.49 was cleaned up and /boot/grub2/grub.cfg to make sure the bootloader was properly updated with kernel 5.14.21-150400.24.46.

# ls -l /boot
# less /boot/grub2/grub.cfg

Step 7: If everything looks good with step 6, reboot.

# /sbin/reboot

Step 8:  Revert steps #2 and 3, so future kernel releases can once again be installed and booted.

This is safe assuming that the .49 kernel has been removed from your maintenance repositories. That is true for SUSE's public repositories, but for 3rd party repositories, you could check with:

zypper lu | grep kernel-default

You can manually edit /etc/zypp/zypp.conf, remove the 2 lines which step #3 added at the end of the file, and uncomment the original multiversion.kernels earlier in the file; or you can use the following two commands to undo those changes:

# sed -i 's/multiversion.kernels/#multiversion.kernels/' /etc/zypp/zypp.conf
# sed -i 's/##multiversion.kernels/multiversion.kernels/' /etc/zypp/zypp.conf