On 03/24/20 at 03:06pm, Sachin Sant wrote: > > > > On 24-Mar-2020, at 2:45 PM, Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com> > > wrote: > > > > Sachin Sant <sach...@linux.vnet.ibm.com> writes: > > > >> While running ndctl[1] tests against 5.6.0-rc7 following crash is > >> encountered. > >> > >> Bisect leads me to commit d41e2f3bd546 > >> mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case > >> > >> Reverting this commit helps and the tests complete without any crash. > > > > > > Can you try this change? > > > > diff --git a/mm/sparse.c b/mm/sparse.c > > index aadb7298dcef..3012d1f3771a 100644 > > --- a/mm/sparse.c > > +++ b/mm/sparse.c > > @@ -781,6 +781,8 @@ 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); > > + /* Mark the section invalid */ > > + ms->section_mem_map &= ~SECTION_HAS_MEM_MAP; > > } > > > > if (section_is_early && memmap) > > > > This patch works for me. The test ran successfully without any crash/failure.
Hi Aneesh, Could you make a formal patch to post, since Sachin has tested and confirmed it works? > > Thanks > -Sachin > > > a pfn_valid check involves pnf_section_valid() check if section is > > having MEM_MAP. In this case we did end up setting the ms->uage = NULL. > > So when we do that tupdate the section to not have MEM_MAP. > > > > -aneesh >