https://jira.whamcloud.com This file is an XML representation of an issue en-us 9.4.14 940014 05-12-2023 https://jira.whamcloud.com/browse/LU-11063 Lustre <p>I finally traced my debug kernel problems with later rhel releases to RCU breakage of some sort.</p> <p>ldlm_locks slab is declared as SLAB_DESTROY_BY_RCU if it's defined This is going back to bugzilla 18015 <a href="https://bugzilla.lustre.org/show_bug.cgi?id=18015" class="external-link" target="_blank" rel="nofollow noopener">https://bugzilla.lustre.org/show_bug.cgi?id=18015</a> patch by BobiJam.</p> <p>Now it appears that as we schedule a free in that slab and then destroy the slab, the actual free is delayed and is executed after the slab is already freed despite rcu_barrier() being present.</p> <p>Clear bug that I will file rh bugzilla ticket for.</p> <p>But in addition to that I wonder how much do we need that thing nowadays, esp. considering that newer kernels renamed the flag to SLAB_TYPESAFE_BY_RCU that we do not detect and just not set it in that case.</p> <p>Should we just convert ldlm_locks into a normal slab again I wonder?</p> LU-11063

RHEL7.[345] RCU breakage

Bug Major Resolved Cannot Reproduce WC Triage Oleg Drokin Tue, 29 May 2018 17:22:48 +0000 Thu, 7 Sep 2023 20:27:46 +0000 Thu, 27 Apr 2023 23:26:54 +0000 Lustre 2.13.0 0 8 <p>This appears to be a deeper case than just removing the flag as was done in this patch <a href="https://review.whamcloud.com/34147" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/34147</a> for <a href="https://jira.whamcloud.com/browse/LU-11568" title="Get rid of SLAB_DESTROY_BY_RCU" class="issue-link" data-issue-key="LU-11568"><del>LU-11568</del></a> and <a href="https://jira.whamcloud.com/browse/LU-12374" title="client went down w/ panic during lustre_rmmod" class="issue-link" data-issue-key="LU-12374"><del>LU-12374</del></a> does not seem to help either.</p> <p>All such crashes are in parallel nfs scale testing on rhel only so I must conclude this is just some deep rhel7 bug.</p> <p>Oleg - DO you think the crash in parallel-scale-nfsv3 racer_on_nfs at <a href="https://testing.whamcloud.com/test_sets/6f865cfa-2575-4ccc-8677-6ff091967e56" class="external-link" target="_blank" rel="nofollow noopener">https://testing.whamcloud.com/test_sets/6f865cfa-2575-4ccc-8677-6ff091967e56</a> is the same issue as this ticket? I ask because this is a SLES 15 SP2 test session. </p> <p>no, it's a different generic kernel bug. The patch for it is here (not sure how you can actually get SuSE to include it though): <a href="https://patchwork.kernel.org/project/linux-nfs/cover/cover.1568377101.git.bcodding@redhat.com/" class="external-link" target="_blank" rel="nofollow noopener">https://patchwork.kernel.org/project/linux-nfs/cover/cover.1568377101.git.bcodding@redhat.com/</a></p> <p>Perhaps <a href="https://jira.whamcloud.com/secure/ViewProfile.jspa?name=neilb" class="user-hover" rel="neilb">neilb</a> would care to comment?</p> <p>If you want to get a patch into SUSE (all upper-case these days) you open an issue on bugzilla.suse.com, and explain what and why.  If you assign the issue to me (or put me on cc or somehow let me know about it - I'm <span class="nobr"><a href="mailto:nfbrown@suse.com" class="external-link" target="_blank" rel="nofollow noopener">nfbrown@suse.com^{<img class="rendericon" src="https://jira.whamcloud.com/images/icons/mail_small.gif" height="12" width="13" align="absmiddle" alt="" border="0"/>}</a></span> in bugzilla) I can expedite it.</p> <p>Or you can ask me directly,  then I can create the bugzilla issue myself.</p> <p>What would be even better would be for these fixup patches to have been marked "Fixes: ......".  Then I would have be alerted to them by our automated machinery.  It's too late for that though...</p> <p> </p> Duplicate LU-12454 Related LU-11568 LU-12374 LU-17097 Bugzilla ID 18015.0 Development Rank 1|hzzxxr: Rank (Obsolete) 9223372036854775807 Severity