+ mm-memory_hotplug-prevent-accessing-by-index=-1.patch added to mm-unstable branch

+ mm-memory_hotplug-prevent-accessing-by-index=-1.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/memory_hotplug: prevent accessing by index=-1
has been added to the -mm mm-unstable branch.  Its filename is
     mm-memory_hotplug-prevent-accessing-by-index=-1.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory_hotplug-prevent-accessing-by-index=-1.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Anastasia Belova <abelova@astralinux.ru>
Subject: mm/memory_hotplug: prevent accessing by index=-1
Date: Thu, 6 Jun 2024 11:06:59 +0300

nid may be equal to NUMA_NO_NODE=-1.  Prevent accessing node_data array by
invalid index with check for nid.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Link: https://lkml.kernel.org/r/20240606080659.18525-1-abelova@astralinux.ru
Fixes: e83a437faa62 ("mm/memory_hotplug: introduce "auto-movable" online policy")
Signed-off-by: Anastasia Belova <abelova@astralinux.ru>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory_hotplug.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/memory_hotplug.c~mm-memory_hotplug-prevent-accessing-by-index=-1
+++ a/mm/memory_hotplug.c
@@ -839,7 +839,6 @@ static bool auto_movable_can_online_mova
 	unsigned long kernel_early_pages, movable_pages;
 	struct auto_movable_group_stats group_stats = {};
 	struct auto_movable_stats stats = {};
-	pg_data_t *pgdat = NODE_DATA(nid);
 	struct zone *zone;
 	int i;
 
@@ -850,6 +849,8 @@ static bool auto_movable_can_online_mova
 			auto_movable_stats_account_zone(&stats, zone);
 	} else {
 		for (i = 0; i < MAX_NR_ZONES; i++) {
+			pg_data_t *pgdat = NODE_DATA(nid);
+
 			zone = pgdat->node_zones + i;
 			if (populated_zone(zone))
 				auto_movable_stats_account_zone(&stats, zone);
_

Patches currently in -mm which might be from abelova@astralinux.ru are

mm-memory_hotplug-prevent-accessing-by-index=-1.patch