Description of problem: Multi-homed Fedora 32 NFS client and server, both with keytabs. Sometimes after performing an NFSv4.0 mount, the sssd_kcm daemon on the server runs at 100% and fills up the sssd_kcm.log file (and eventually, the root partition). (2020-08-10 15:03:04:680265): [kcm] [kcm_input_parse] (0x1000): Received message with length 0 (2020-08-10 15:03:04:680284): [kcm] [kcm_input_parse] (0x0020): Illegal zero-length message (2020-08-10 15:03:04:680302): [kcm] [kcm_recv] (0x0010): Failed to parse data (74, Bad message), aborting client (2020-08-10 15:03:04:680319): [kcm] [kcm_reply_error] (0x0040): KCM operation returs failure [74]: Bad message (2020-08-10 15:03:04:680353): [kcm] [kcm_failbuf_construct] (0x1000): Sent reply with error -1765328188 Version-Release number of selected component (if applicable): sssd-kcm-2.3.1-2.fc32.x86_64 How reproducible: Happens every second or third mount operation. Steps to Reproduce: 1. Set up NFS client and server with keytabs 2. Repeat: "mount -o vers=4.0,sec=sys" / do some operations / umount 3. Watch the server with "top" Actual results: Sometimes sssd_kcm goes to 100% of a CPU and must be killed. Expected results: No looping. Additional info: The NFSv4.0 backchannel, in this case, is secured with GSS krb5i. It appears that gssd on the server is accessing the Kerberos ticket cache while setting up the backchannel, and sometimes this triggers the kcm loop.
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Fedora 32 changed to end-of-life (EOL) status on 2021-05-25. Fedora 32 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.