On Thu 16-01-20 11:01:08, Pingfan Liu wrote: > When fully deactivated, it is meaningless to keep the value of a section's > mem_map. And its mem_map will be reassigned during re-added. > > Beside this, it breaks the user space tool "makedumpfile", which makes > assumption that a hot-removed section having mem_map as NULL.
We used to do that before ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug"). Dan was this an intentional change? > The bug can be reproduced on IBM POWERVM by "drmgr -c mem -r -q 5" , > trigger a crash, and save vmcore by makedumpfile > > Signed-off-by: Pingfan Liu <kernelf...@gmail.com> > To: linux...@kvack.org > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: David Hildenbrand <da...@redhat.com> > Cc: Dan Williams <dan.j.willi...@intel.com> > Cc: Oscar Salvador <osalva...@suse.de> > Cc: Michal Hocko <mho...@kernel.org> > Cc: kexec@lists.infradead.org > Cc: Kazuhito Hagio <k-ha...@ab.jp.nec.com> > --- > mm/sparse.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/sparse.c b/mm/sparse.c > index 3822ecb..fddac80 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -789,7 +789,7 @@ static void section_deactivate(unsigned long pfn, > unsigned long nr_pages, > ms->usage = NULL; > } > memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); > - ms->section_mem_map = sparse_encode_mem_map(NULL, section_nr); > + ms->section_mem_map = NULL; > } > > if (section_is_early && memmap) > -- > 2.7.5 -- Michal Hocko SUSE Labs _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec