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-12640 Lustre <p> The checking and assgin below could be racy:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre> if (lu_env_percpu[i].lep_task == current) { env = lu_env_percpu[i].lep_env; CPU0 thread0 lu_env_percpu[i].lep_task == current thread1 switch into CPU0 changes lu_env_percpu[0] thread0 switch back CPU0,return lu_env_percpu[0].lep_env; </pre> </div></div> <p> The problem is access and change per_cpu variable here<br/> shall be atomic, since it is per cpu variable, we should<br/> take care it not been preempted.</p> LU-12640

per cpu env race

Bug Minor Closed Cannot Reproduce Wang Shilong Wang Shilong Thu, 8 Aug 2019 08:11:16 +0000 Sat, 16 May 2020 00:35:51 +0000 Sat, 16 May 2020 00:35:51 +0000 0 4 <p>get_cpu() line above is supposed to prevent scheduling.</p> <p>Wang Shilong (wshilong@ddn.com) uploaded a new patch: <a href="https://review.whamcloud.com/35728" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/35728</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-12640" title="per cpu env race" class="issue-link" data-issue-key="LU-12640"><del>LU-12640</del></a> obdclass: percpu env race<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 74e41620a79f6ba97d02638e4e4b9b57a891a729</p> <p>Shilong, how often are you seeing this? I don't see any stack dumps in this ticket, links to other tickets, links to failures in Maloo, bug reproducer test case in the patch, etc., so it seems very unlikely to happed in real life? I'm wondering if I (or, preferably, you) need to chase reviewers, or it should be closed with "Cannot Reproduce" and the patch abandoned until someone hits it again (which would be easier to find if there was a stack trace in this ticket).</p> Development Rank 1|i00kvj: Rank (Obsolete) 9223372036854775807 Severity