Resource temporarily unavailable on cifs mountpoint, mounted with sec=krb5 option

[Vladimir Vershinin]

I need to use krb5 authentication for mounting smb shares.

My OS details

PRETTY_NAME="Ubuntu 20.04.4 LTS"
linux-image-5.4.0-125-generic
krb5-user 1.17-6ubuntu4.4
cifs-utils 2:6.9-1ubuntu0.2
keyutils 1.6-6ubuntu1.1

I have workable krb and request-key configs. The mountpiont record in fstab

//fs.server.local/share /mnt/share cifs sec=krb5,user=smbuser,iocharset=utf8,uid=****,gid=****

And everything work until (I think) the krb ticked expires.
After krb ticket expiration I have got an "Resource temporarily unavailable" error

ls /mnt/share
ls: reading directory '/mnt/share/': Resource temporarily unavailable

According the syslog, at this time the krb ticket is refreshed by the cufs.upcall tool

Feb 5 08:16:24 smbclient.server.local cifs.upcall: key description: cifs.spnego;0;0;39010000;ver=0x2;host=fs.server.local;ip4=*.*.*.*;sec=krb5;uid=0x
fffe;creduid=0x0;user=usrappsflyer;pid=0x919e5
Feb 5 08:16:24 cifs.upcall: ver=2
Feb 5 08:16:24 smbclient.server.local cifs.upcall: host=fs.server.local
Feb 5 08:16:24 smbclient.server.local cifs.upcall: ip=*.*.*.*
Feb 5 08:16:24 smbclient.server.local cifs.upcall: sec=1
Feb 5 08:16:24 smbclient.server.local cifs.upcall: uid=*****
Feb 5 08:16:24 smbclient.server.local cifs.upcall: creduid=0
Feb 5 08:16:24 smbclient.server.local cifs.upcall: user=usrappsflyer
Feb 5 08:16:24 smbclient.server.local cifs.upcall: pid=*****
Feb 5 08:16:24 smbclient.server.local cifs.upcall: get_cachename_from_process_env: pid == 0
Feb 5 08:16:24 smbclient.server.local cifs.upcall: get_existing_cc: default ccache is FILE:/tmp/krb5cc_0
Feb 5 08:16:24 smbclient.server.local cifs.upcall: get_tgt_time: unable to get principal
Feb 5 08:16:24 smbclient.server.local cifs.upcall: handle_krb5_mech: getting service ticket for fs.server.local/
Feb 5 08:16:24 smbclient.server.local cifs.upcall: handle_krb5_mech: obtained service ticket
Feb 5 08:16:24 smbclient.server.local cifs.upcall: Exit status 0

And mountpoint become available till next krb ticket expiration.

How I can remove the "Resource temporarily unavailable" error in this case?

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Libera.chat.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/2052430/+editstatus and add the package name in the text box next to the word Package.

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