On Thu 06-11-14 16:08:02, Weijie Yang wrote: > In the undo path of start_isolate_page_range(), we need to check > the pfn validity before access its page, or it will trigger an > addressing exception if there is hole in the zone.
This looks a bit fishy to me. I am not familiar with the code much but at least __offline_pages zone = page_zone(pfn_to_page(start_pfn)) so it would blow up before we got here. Same applies to the other caller alloc_contig_range. So either both need a fix and then start_isolate_page_range doesn't need more checks or this is all unnecessary. Please do not make this code more obfuscated than it is already... > Signed-off-by: Weijie Yang <[email protected]> > --- > mm/page_isolation.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/mm/page_isolation.c b/mm/page_isolation.c > index d1473b2..3ddc8b3 100644 > --- a/mm/page_isolation.c > +++ b/mm/page_isolation.c > @@ -137,8 +137,11 @@ int start_isolate_page_range(unsigned long start_pfn, > unsigned long end_pfn, > undo: > for (pfn = start_pfn; > pfn < undo_pfn; > - pfn += pageblock_nr_pages) > - unset_migratetype_isolate(pfn_to_page(pfn), migratetype); > + pfn += pageblock_nr_pages) { > + page = __first_valid_page(pfn, pageblock_nr_pages); > + if (page) > + unset_migratetype_isolate(page, migratetype); > + } > > return -EBUSY; > } > -- > 1.7.0.4 > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to [email protected]. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"[email protected]";> [email protected] </a> -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
