linux-kernel - [PATCH 1/1] mm: kfence: skip kmemleak alloc in kfence

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Message-ID: <20220623111937.6491-2-yee.lee@mediatek.com>
Date:   Thu, 23 Jun 2022 19:19:35 +0800
From:   <yee.lee@...iatek.com>
To:     <linux-kernel@...r.kernel.org>
CC:     Yee Lee <yee.lee@...iatek.com>,
        Alexander Potapenko <glider@...gle.com>,
        Marco Elver <elver@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        "Andrew Morton" <akpm@...ux-foundation.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "open list:KFENCE" <kasan-dev@...glegroups.com>,
        "open list:MEMORY MANAGEMENT" <linux-mm@...ck.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>
Subject: [PATCH 1/1] mm: kfence: skip kmemleak alloc in kfence_pool

From: Yee Lee <yee.lee@...iatek.com>

Use MEMBLOCK_ALLOC_NOLEAKTRACE to skip kmemleak registration when
the kfence pool is allocated from memblock. And the kmemleak_free
later can be removed too.

Signed-off-by: Yee Lee <yee.lee@...iatek.com>

---
 mm/kfence/core.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 4e7cd4c8e687..0d33d83f5244 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -600,14 +600,6 @@ static unsigned long kfence_init_pool(void)
 		addr += 2 * PAGE_SIZE;
 	}
 
-	/*
-	 * The pool is live and will never be deallocated from this point on.
-	 * Remove the pool object from the kmemleak object tree, as it would
-	 * otherwise overlap with allocations returned by kfence_alloc(), which
-	 * are registered with kmemleak through the slab post-alloc hook.
-	 */
-	kmemleak_free(__kfence_pool);
-
 	return 0;
 }
 
@@ -831,8 +823,14 @@ void __init kfence_alloc_pool(void)
 {
 	if (!kfence_sample_interval)
 		return;
-
-	__kfence_pool = memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE);
+	/*
+	 * The pool is live and will never be deallocated from this point on.
+	 * Skip the pool object from the kmemleak object allocation, as it would
+	 * otherwise overlap with allocations returned by kfence_alloc(), which
+	 * are registered with kmemleak through the slab post-alloc hook.
+	 */
+	__kfence_pool = memblock_alloc_try_nid(KFENCE_POOL_SIZE, PAGE_SIZE,
+		 MEMBLOCK_LOW_LIMIT, MEMBLOCK_ALLOC_NOLEAKTRACE, NUMA_NO_NODE);
 
 	if (!__kfence_pool)
 		pr_err("failed to allocate pool\n");
-- 
2.18.0