[LU-1820] (genops.c:766:class_export_destroy()) ASSERTION(cfs_list_empty(&exp->exp_hp_rpcs)) failed

• Status: Closed
• Project: Lustre
• Affects Version/s: Lustre 2.1.0, Lustre 2.2.0, Lustre 2.3.0, Lustre 2.4.0
• Fix Version/s: Lustre 2.3.0, Lustre 2.4.0
• Type: Bug
• Priority: Blocker
• Reporter: Alexander Boyko
• Assignee: Mikhail Pershin
• Resolution: Fixed
• Labels: MB, patch
• Severity: 3

Description

ptlrpc_server_handle_req_in() call ptlrpc_server_request_add()
and hp request can be added to export->exp_hp_rpcs, but reference
increase at ptlrpc_server_handle_request(). If class_disconnect() and
class_export_destroy() occures before ptlrpc_server_handle_request()
we got ASSERTION.

Comments

[Alexander Boyko]

req http://review.whamcloud.com/3855

[Peter Jones]

Liang

Could you please make the necessary revisions to the existing patch?

Thanks

Peter

[Peter Jones]

Landed for 2.3 and 2.4

[Nathan Rutman]

Xyratex-bug-id: MRP-649

[Alexander Boyko]

We have seen this assert again, sources contain the fix http://review.whamcloud.com/3855.

The root cause of this bugs is the next part of target_handle_connect()

        if (req->rq_export != NULL)
                class_export_put(req->rq_export);
        /* request takes one export refcount */
        req->rq_export = class_export_get(export);

req->rq_export was changed but export contain hp request (this is valid after connect became hp req).
And after that at ptlrpc_server_handle_req()

out_req:
       if (export != NULL)
               class_export_rpc_put(export);
       ptlrpc_server_finish_request(svcpt, request);

1) delete last reference for the first export with hp req
2) ptlrpc_server_hpreq_fini() delete list entry for hp req

This invalid logic cause topic assert.
Request for review to fix this - http://review.whamcloud.com/#change,5922.

[Oleg Drokin]

Reopening in light of new evidence that the previous fix was incomplete

[Peter Jones]

Mike can you please review this latest patch?

[Peter Jones]

Landed for 2.4

[Alexander Boyko]

Xyratex-bug-id: MRP-881