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* [PATCH] mm/large system hash: avoid possible NULL deref in alloc_large_system_hash
@ 2021-09-15 21:25 Eric Dumazet
  0 siblings, 0 replies; only message in thread
From: Eric Dumazet @ 2021-09-15 21:25 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-kernel, Eric Dumazet, Eric Dumazet, Nicholas Piggin

From: Eric Dumazet <edumazet@google.com>

If __vmalloc() returned NULL, is_vm_area_hugepages(NULL) will fault
if CONFIG_HAVE_ARCH_HUGE_VMALLOC=y

Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
---
 mm/page_alloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b37435c274cf1cb1fabd26465ca7899bb610d91f..e115e21524739341d409b28379942241ed403060 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8756,7 +8756,8 @@ void *__init alloc_large_system_hash(const char *tablename,
 		} else if (get_order(size) >= MAX_ORDER || hashdist) {
 			table = __vmalloc(size, gfp_flags);
 			virt = true;
-			huge = is_vm_area_hugepages(table);
+			if (table)
+				huge = is_vm_area_hugepages(table);
 		} else {
 			/*
 			 * If bucketsize is not a power-of-two, we may free
-- 
2.33.0.309.g3052b89438-goog


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2021-09-15 21:25 [PATCH] mm/large system hash: avoid possible NULL deref in alloc_large_system_hash Eric Dumazet

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