malloc maintains a linked list of arenas which were used by threads at the time they exited. New threads receive arenas from this list, in the expectation that they are unused and uncontended. However, due to an incorrect assumption (one arena can be attached to several threads), the free list could turn cyclic. If this happens, a potentially small set of arenas will be assigned to all new threads. This bug is not a correctness issue, but it can significantly reduce application performance. qemu-kvm and OpenJDK have been observed to trigger this bug.
Patch posted for review: https://lists.fedoraproject.org/pipermail/glibc/2015-October/000090.html
glibc-2.21-10.fc22 has been submitted as an update to Fedora 22. https://bodhi.fedoraproject.org/updates/FEDORA-2016-0480defc94
glibc-2.21-10.fc22 has been pushed to the Fedora 22 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2016-0480defc94
glibc-2.21-11.fc22 has been submitted as an update to Fedora 22. https://bodhi.fedoraproject.org/updates/FEDORA-2016-0480defc94
glibc-2.21-11.fc22 has been pushed to the Fedora 22 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2016-0480defc94
glibc-2.21-11.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.