+++ /dev/null
-From 00d6c019b5bc175cee3770e0e659f2b5f4804ea5 Mon Sep 17 00:00:00 2001
-From: David Hildenbrand <david@redhat.com>
-Date: Fri, 18 Oct 2019 20:19:33 -0700
-Subject: mm/memory_hotplug: don't access uninitialized memmaps in shrink_pgdat_span()
-
-From: David Hildenbrand <david@redhat.com>
-
-commit 00d6c019b5bc175cee3770e0e659f2b5f4804ea5 upstream.
-
-We might use the nid of memmaps that were never initialized. For
-example, if the memmap was poisoned, we will crash the kernel in
-pfn_to_nid() right now. Let's use the calculated boundaries of the
-separate zones instead. This now also avoids having to iterate over a
-whole bunch of subsections again, after shrinking one zone.
-
-Before commit d0dc12e86b31 ("mm/memory_hotplug: optimize memory
-hotplug"), the memmap was initialized to 0 and the node was set to the
-right value. After that commit, the node might be garbage.
-
-We'll have to fix shrink_zone_span() next.
-
-Link: http://lkml.kernel.org/r/20191006085646.5768-4-david@redhat.com
-Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [d0dc12e86b319]
-Signed-off-by: David Hildenbrand <david@redhat.com>
-Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
-Cc: Oscar Salvador <osalvador@suse.de>
-Cc: David Hildenbrand <david@redhat.com>
-Cc: Michal Hocko <mhocko@suse.com>
-Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
-Cc: Dan Williams <dan.j.williams@intel.com>
-Cc: Wei Yang <richardw.yang@linux.intel.com>
-Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
-Cc: Alexander Potapenko <glider@google.com>
-Cc: Andy Lutomirski <luto@kernel.org>
-Cc: Anshuman Khandual <anshuman.khandual@arm.com>
-Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-Cc: Borislav Petkov <bp@alien8.de>
-Cc: Catalin Marinas <catalin.marinas@arm.com>
-Cc: Christian Borntraeger <borntraeger@de.ibm.com>
-Cc: Christophe Leroy <christophe.leroy@c-s.fr>
-Cc: Damian Tometzki <damian.tometzki@gmail.com>
-Cc: Dave Hansen <dave.hansen@linux.intel.com>
-Cc: Fenghua Yu <fenghua.yu@intel.com>
-Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
-Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-Cc: Halil Pasic <pasic@linux.ibm.com>
-Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
-Cc: "H. Peter Anvin" <hpa@zytor.com>
-Cc: Ingo Molnar <mingo@redhat.com>
-Cc: Ira Weiny <ira.weiny@intel.com>
-Cc: Jason Gunthorpe <jgg@ziepe.ca>
-Cc: Jun Yao <yaojun8558363@gmail.com>
-Cc: Logan Gunthorpe <logang@deltatee.com>
-Cc: Mark Rutland <mark.rutland@arm.com>
-Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
-Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
-Cc: Mel Gorman <mgorman@techsingularity.net>
-Cc: Michael Ellerman <mpe@ellerman.id.au>
-Cc: Mike Rapoport <rppt@linux.ibm.com>
-Cc: Pankaj Gupta <pagupta@redhat.com>
-Cc: Paul Mackerras <paulus@samba.org>
-Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
-Cc: Peter Zijlstra <peterz@infradead.org>
-Cc: Qian Cai <cai@lca.pw>
-Cc: Rich Felker <dalias@libc.org>
-Cc: Robin Murphy <robin.murphy@arm.com>
-Cc: Steve Capper <steve.capper@arm.com>
-Cc: Thomas Gleixner <tglx@linutronix.de>
-Cc: Tom Lendacky <thomas.lendacky@amd.com>
-Cc: Tony Luck <tony.luck@intel.com>
-Cc: Vasily Gorbik <gor@linux.ibm.com>
-Cc: Vlastimil Babka <vbabka@suse.cz>
-Cc: Wei Yang <richard.weiyang@gmail.com>
-Cc: Will Deacon <will@kernel.org>
-Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
-Cc: Yu Zhao <yuzhao@google.com>
-Cc: <stable@vger.kernel.org> [4.13+]
-Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- mm/memory_hotplug.c | 74 +++++++++++-----------------------------------------
- 1 file changed, 16 insertions(+), 58 deletions(-)
-
---- a/mm/memory_hotplug.c
-+++ b/mm/memory_hotplug.c
-@@ -436,67 +436,25 @@ static void shrink_zone_span(struct zone
- zone_span_writeunlock(zone);
- }
-
--static void shrink_pgdat_span(struct pglist_data *pgdat,
-- unsigned long start_pfn, unsigned long end_pfn)
-+static void update_pgdat_span(struct pglist_data *pgdat)
- {
-- unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
-- unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
-- unsigned long pgdat_end_pfn = p;
-- unsigned long pfn;
-- int nid = pgdat->node_id;
--
-- if (pgdat_start_pfn == start_pfn) {
-- /*
-- * If the section is smallest section in the pgdat, it need
-- * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
-- * In this case, we find second smallest valid mem_section
-- * for shrinking zone.
-- */
-- pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
-- pgdat_end_pfn);
-- if (pfn) {
-- pgdat->node_start_pfn = pfn;
-- pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
-- }
-- } else if (pgdat_end_pfn == end_pfn) {
-- /*
-- * If the section is biggest section in the pgdat, it need
-- * shrink pgdat->node_spanned_pages.
-- * In this case, we find second biggest valid mem_section for
-- * shrinking zone.
-- */
-- pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
-- start_pfn);
-- if (pfn)
-- pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
-- }
--
-- /*
-- * If the section is not biggest or smallest mem_section in the pgdat,
-- * it only creates a hole in the pgdat. So in this case, we need not
-- * change the pgdat.
-- * But perhaps, the pgdat has only hole data. Thus it check the pgdat
-- * has only hole or not.
-- */
-- pfn = pgdat_start_pfn;
-- for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SUBSECTION) {
-- if (unlikely(!pfn_valid(pfn)))
-- continue;
--
-- if (pfn_to_nid(pfn) != nid)
-- continue;
--
-- /* Skip range to be removed */
-- if (pfn >= start_pfn && pfn < end_pfn)
-- continue;
-+ unsigned long node_start_pfn = 0, node_end_pfn = 0;
-+ struct zone *zone;
-
-- /* If we find valid section, we have nothing to do */
-- return;
-+ for (zone = pgdat->node_zones;
-+ zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
-+ unsigned long zone_end_pfn = zone->zone_start_pfn +
-+ zone->spanned_pages;
-+
-+ /* No need to lock the zones, they can't change. */
-+ if (zone_end_pfn > node_end_pfn)
-+ node_end_pfn = zone_end_pfn;
-+ if (zone->zone_start_pfn < node_start_pfn)
-+ node_start_pfn = zone->zone_start_pfn;
- }
-
-- /* The pgdat has no valid section */
-- pgdat->node_start_pfn = 0;
-- pgdat->node_spanned_pages = 0;
-+ pgdat->node_start_pfn = node_start_pfn;
-+ pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
- }
-
- static void __remove_zone(struct zone *zone, unsigned long start_pfn,
-@@ -507,7 +465,7 @@ static void __remove_zone(struct zone *z
-
- pgdat_resize_lock(zone->zone_pgdat, &flags);
- shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
-- shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
-+ update_pgdat_span(pgdat);
- pgdat_resize_unlock(zone->zone_pgdat, &flags);
- }
-
projects / thirdparty / kernel / stable-queue.git / commitdiff
