On Tue, 1 Mar 2016 06:14:32 +0000 Atsushi Kumagai <ats-kumagai at wm.jp.nec.com> wrote: > makedumpfile refers page.lru.next to get the order of compound pages > for page filtering. However, now the order is stored in page.compound_order, > hence VMCOREINFO should be updated to export the offset of > page.compound_order. > > The fact is, page.compound_order was introduced already in kernel 4.0, > but the offset of it was the same as page.lru.next until kernel 4.3, > so this was not actual problem. > > The above can be said also for page.lru.prev and page.compound_dtor, > it's necessary to detect hugetlbfs pages. Further, the content was > changed from direct address to the ID which means dtor. It's unclear which kernels need the patch and why. I *think* that the patch is needed in 4.3.x, 4.4.x, 4.5.x and 4.6 in order to make makedumpfile work correctly. Is that right? And it appears that [patch 2/2] is needed in 4.0+? However in both cases I am uncertain - what are the end-user visible effects of these regressions? Why can bugs remain in place for so long without having been observed? Please make all these things clear when perparing changelogs for bugfixes: which kernel versions need fixing and why (ie: what are the end-user visible effects of the bug).
