[LU-39] ASSERTION(atomic_read(&client_stat->nid_exp_ref_count) == 0) failed: count 1

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.1.0, Lustre 1.8.6
• Affects Version/s: Lustre 1.8.6
• Environment: lustre 1.8.3.0-6chaos
• Severity: 3
• Bugzilla ID: 23,499
• Assignee: Zhenyu Xu
• Reporter: Christopher Morrone (Inactive)

Description

A sysadmin was shutting down an MDS node cleanly in preparation for scheduled upgrades. During the umount of the MGS device, we hit the following assertion:

LustreError ... (lprocfs_status.c:1060:lprocfs_free_client_stats())
ASSERTION(atomic_read(&client_stat->nid_exp_ref_count) == 0) failed: count 1

And the stack trace was:

:obdclass:lprocfs_free_client_stats
:obdclass:lprocfs_free_per_client_stats
:mgs:lproc_mgs_cleanup
:mgs:mgs_cleanup
:obdclass:class_decref
:obdclass:class_export_destroy
:obdclass:obd_zombie_impexp_cull
:obdclass:obd_zombie_impexp_thread

We have seen this same assertion from OSTs as well. Some investigation was done in bug 23499, but there is not yet a solution.