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From:   Mike Rapoport <rppt@linux.ibm.com>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Mike Rapoport <rppt@linux.ibm.com>
Subject: [PATCH] mm/page_alloc: check return value of memblock_alloc_node_nopanic()
Date:   Wed, 16 Jan 2019 08:51:21 +0200
Message-Id: <1547621481-8374-1-git-send-email-rppt@linux.ibm.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

There are two early memory allocations that use
memblock_alloc_node_nopanic() and do not check its return value.
While this happens very early during boot and chances that the allocation
will fail are diminishing, it is still worth to have proper checks for the
allocation errors.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
 mm/page_alloc.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d295c9bc01a8..7801accbe02a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6376,10 +6376,14 @@ static void __ref setup_usemap(struct pglist_data *pgdat,
 {
 	unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
 	zone->pageblock_flags = NULL;
-	if (usemapsize)
+	if (usemapsize) {
 		zone->pageblock_flags =
 			memblock_alloc_node_nopanic(usemapsize,
 							 pgdat->node_id);
+		if (!zone->pageblock_flags)
+			panic("Failed to allocate %ld bytes for zone %s pageblock flags\n",
+			      usemapsize, zone->name);
+	}
 }
 #else
 static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
@@ -6609,6 +6613,9 @@ static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
 		end = ALIGN(end, MAX_ORDER_NR_PAGES);
 		size =  (end - start) * sizeof(struct page);
 		map = memblock_alloc_node_nopanic(size, pgdat->node_id);
+		if (!map)
+			panic("Failed to allocate %ld bytes for memory map\n",
+			      size);
 		pgdat->node_mem_map = map + offset;
 	}
 	pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
-- 
2.7.4