Hello everyone:

We recently upgrade slurm to 25.11 and find the pam_slurm_adopt got broken. This cause the users cannot ssh to the compute node where their jobs is running on.

Of course we have make sure all the slurm related packages have been upgraded together.

Simplest test process is like:

```

> cat test1.sh

#!/bin/bash

#SBATCH --job-name=test

#SBATCH --partition=debug

#SBATCH --nodes=1

#SBATCH --nodelist=cas639

sleep 6000

> sbatch test1.sh

Submitted batch job 51047091

> squeue

             JOBID PARTITION     NAME     USER ST       TIME  NODES NODELIST(REASON)

          51047091     debug     test   tester  R       0:28      1 cas639

> ssh cas639

(wait for a long time...)

Connection closed by 172.16.3.129 port 22 (finally failed to ssh)

```

on the target compute node, we can see the following debug message from pam_slurm_adopt.so:

```

cas639 pam_slurm_adopt[1007301]: debug2: _establish_config_source: using config_file=/etc/slurm/slurm.conf (default)

cas639 pam_slurm_adopt[1007301]: debug:  slurm_conf_init: using config_file=/etc/slurm/slurm.conf

cas639 pam_slurm_adopt[1007301]: debug:  Reading slurm.conf file: /etc/slurm/slurm.conf

cas639 pam_slurm_adopt[1007301]: PreemptMode=GANG is a cluster-wide option and cannot be set at partition level, option ignored.

cas639 pam_slurm_adopt[1007301]: debug3: Trying to load plugin /usr/lib64/slurm/auth_munge.so

cas639 pam_slurm_adopt[1007301]: debug3: plugin_load_from_file->_verify_syms: found Slurm plugin name:Munge authentication plugin type:auth/munge version:0x190b00

cas639 pam_slurm_adopt[1007301]: debug:  auth/munge: init: loaded

cas639 pam_slurm_adopt[1007301]: debug3: Success.

cas639 pam_slurm_adopt[1007301]: debug3: Trying to load plugin /usr/lib64/slurm/certgen_script.so

cas639 pam_slurm_adopt[1007301]: debug3: plugin_load_from_file->_verify_syms: found Slurm plugin name:Certificate generation script plugin type:certgen/script version:0x190b00

cas639 pam_slurm_adopt[1007301]: debug:  certgen/script: init: loaded

cas639 pam_slurm_adopt[1007301]: debug3: Success.

cas639 pam_slurm_adopt[1007301]: debug3: Trying to load plugin /usr/lib64/slurm/hash_k12.so

cas639 pam_slurm_adopt[1007301]: debug3: plugin_load_from_file->_verify_syms: found Slurm plugin name:KangarooTwelve hash plugin type:hash/k12 version:0x190b00

cas639 pam_slurm_adopt[1007301]: debug:  hash/k12: init: init: KangarooTwelve hash plugin loaded

cas639 pam_slurm_adopt[1007301]: debug3: Success.

cas639 pam_slurm_adopt[1007301]: debug3: Trying to load plugin /usr/lib64/slurm/tls_none.so

cas639 pam_slurm_adopt[1007301]: debug3: plugin_load_from_file->_verify_syms: found Slurm plugin name:Null tls plugin type:tls/none version:0x190b00

cas639 pam_slurm_adopt[1007301]: debug:  tls/none: init: tls/none loaded

cas639 pam_slurm_adopt[1007301]: debug3: Success.

cas639 pam_slurm_adopt[1007301]: debug3: Trying to load plugin /usr/lib64/slurm/accounting_storage_slurmdbd.so

cas639 pam_slurm_adopt[1007301]: debug3: plugin_load_from_file->_verify_syms: found Slurm plugin name:Accounting storage SLURMDBD plugin type:accounting_storage/slurmdbd version:0x190b00

cas639 pam_slurm_adopt[1007301]: accounting_storage/slurmdbd: init: Accounting storage SLURMDBD plugin loaded

cas639 pam_slurm_adopt[1007301]: debug3: Success.

cas639 pam_slurm_adopt[1007301]: debug3: Trying to load plugin /usr/lib64/slurm/cred_munge.so

cas639 pam_slurm_adopt[1007301]: debug3: plugin_load_from_file->_verify_syms: found Slurm plugin name:Munge credential signature plugin type:cred/munge version:0x190b00

cas639 pam_slurm_adopt[1007301]: cred/munge: init: Munge credential signature plugin loaded

cas639 pam_slurm_adopt[1007301]: debug3: Success.

cas639 pam_slurm_adopt[1007301]: debug:  Reading cgroup.conf file /etc/slurm/cgroup.conf

cas639 pam_slurm_adopt[1007301]: debug4: found StepId=51047091.extern

cas639 pam_slurm_adopt[1007301]: debug4: found StepId=51047091.batch

cas639 pam_slurm_adopt[1007301]: Connection by user tester: user has only one job 51047091

cas639 pam_slurm_adopt[1007301]: debug:  _adopt_process: trying to get StepId=51047091.extern to adopt 1007301

cas639 pam_slurm_adopt[1007301]: debug:  Leaving stepd_add_extern_pid

cas639 pam_slurm_adopt[1007301]: debug:  Leaving stepd_get_x11_display

cas639 pam_slurm_adopt[1007301]: debug:  entering stepd_get_namespace_fd

```

It looks like something block during stepd_get_namespace_fd? And we found nothing in slurmd log even with SlurmdDebug = debug5, so I guess the pam module had not run to the step to talk with slurmd (if it should).

Would it be a compatibility problem between slurm25.11 and EL8 system or cgroup/v1?

Or can anyone help to give some suggestion on how to further locate the fault point?

Best regards,

Hermes