On Thu, Apr 26, 2018 at 04:30:02PM -0400, Pavel Tatashin wrote: > Memory hotplug, and hotremove operate with per-block granularity. If > machine has large amount of memory (more than 64G), the size of memory > block can span multiple sections. By mistake, during hotremove we set > only the first section to offline state. > > The bug was discovered because kernel selftest started to fail: > https://lkml.kernel.org/r/20180423011247.GK5563@yexl-desktop > > After commit, "mm/memory_hotplug: optimize probe routine". But, the bug is > older than this commit. In this optimization we also added a check for > sections to be in a proper state during hotplug operation. > > Fixes: 2d070eab2e82 ("mm: consider zone which is not fully populated to have holes") > > Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> > Acked-by: Michal Hocko <mhocko@xxxxxxxx> > --- > mm/sparse.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/sparse.c b/mm/sparse.c > index 62eef264a7bd..73dc2fcc0eab 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -629,7 +629,7 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn) > unsigned long pfn; > > for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { > - unsigned long section_nr = pfn_to_section_nr(start_pfn); > + unsigned long section_nr = pfn_to_section_nr(pfn); > struct mem_section *ms; > > /* > -- > 2.17.0 <formletter> This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly. </formletter>