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From:   Muchun Song <songmuchun@bytedance.com>
To:     glider@google.com, elver@google.com, dvyukov@google.com,
        akpm@linux-foundation.org, jannh@google.com, sjpark@amazon.de,
        muchun.song@linux.dev
Cc:     kasan-dev@googlegroups.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH 2/6] mm: kfence: check kfence pool size at building time
Date:   Tue, 28 Mar 2023 17:58:03 +0800
Message-Id: <20230328095807.7014-3-songmuchun@bytedance.com>
In-Reply-To: <20230328095807.7014-1-songmuchun@bytedance.com>
References: <20230328095807.7014-1-songmuchun@bytedance.com>
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Check kfence pool size at building time to expose problem ASAP.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 mm/kfence/core.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index de62a84d4830..6781af1dfa66 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -841,10 +841,9 @@ static int kfence_init_late(void)
 		return -ENOMEM;
 	__kfence_pool = page_to_virt(pages);
 #else
-	if (nr_pages > MAX_ORDER_NR_PAGES) {
-		pr_warn("KFENCE_NUM_OBJECTS too large for buddy allocator\n");
-		return -EINVAL;
-	}
+	BUILD_BUG_ON_MSG(get_order(KFENCE_POOL_SIZE) > MAX_ORDER,
+			 "CONFIG_KFENCE_NUM_OBJECTS is too large for buddy allocator");
+
 	__kfence_pool = alloc_pages_exact(KFENCE_POOL_SIZE, GFP_KERNEL);
 	if (!__kfence_pool)
 		return -ENOMEM;
-- 
2.11.0