linux-kernel - [PATCH v2 07/10] kfence, kmemleak: make KFENCE compatible with KMEMLEAK

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Message-Id: <20200915132046.3332537-8-elver@google.com>
Date:   Tue, 15 Sep 2020 15:20:43 +0200
From:   Marco Elver <elver@...gle.com>
To:     elver@...gle.com, akpm@...ux-foundation.org, glider@...gle.com
Cc:     hpa@...or.com, paulmck@...nel.org, andreyknvl@...gle.com,
        aryabinin@...tuozzo.com, luto@...nel.org, bp@...en8.de,
        catalin.marinas@....com, cl@...ux.com, dave.hansen@...ux.intel.com,
        rientjes@...gle.com, dvyukov@...gle.com, edumazet@...gle.com,
        gregkh@...uxfoundation.org, mingo@...hat.com, jannh@...gle.com,
        Jonathan.Cameron@...wei.com, corbet@....net,
        iamjoonsoo.kim@....com, keescook@...omium.org,
        mark.rutland@....com, penberg@...nel.org, peterz@...radead.org,
        cai@....pw, tglx@...utronix.de, vbabka@...e.cz, will@...nel.org,
        x86@...nel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, kasan-dev@...glegroups.com,
        linux-arm-kernel@...ts.infradead.org, linux-mm@...ck.org
Subject: [PATCH v2 07/10] kfence, kmemleak: make KFENCE compatible with KMEMLEAK

From: Alexander Potapenko <glider@...gle.com>

Add compatibility with KMEMLEAK, by making KMEMLEAK aware of the KFENCE
memory pool. This allows building debug kernels with both enabled, which
also helped in debugging KFENCE.

Co-developed-by: Marco Elver <elver@...gle.com>
Signed-off-by: Marco Elver <elver@...gle.com>
Signed-off-by: Alexander Potapenko <glider@...gle.com>
---
v2:
* Rework using delete_object_part() [suggested by Catalin Marinas].
---
 mm/kmemleak.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 5e252d91eb14..feff16068e8e 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -97,6 +97,7 @@
 #include <linux/atomic.h>
 
 #include <linux/kasan.h>
+#include <linux/kfence.h>
 #include <linux/kmemleak.h>
 #include <linux/memory_hotplug.h>
 
@@ -1948,6 +1949,11 @@ void __init kmemleak_init(void)
 		      KMEMLEAK_GREY, GFP_ATOMIC);
 	create_object((unsigned long)__bss_start, __bss_stop - __bss_start,
 		      KMEMLEAK_GREY, GFP_ATOMIC);
+#if defined(CONFIG_KFENCE) && defined(CONFIG_HAVE_ARCH_KFENCE_STATIC_POOL)
+	/* KFENCE objects are located in .bss, which may confuse kmemleak. Skip them. */
+	delete_object_part((unsigned long)__kfence_pool, KFENCE_POOL_SIZE);
+#endif
+
 	/* only register .data..ro_after_init if not within .data */
 	if (&__start_ro_after_init < &_sdata || &__end_ro_after_init > &_edata)
 		create_object((unsigned long)__start_ro_after_init,
-- 
2.28.0.618.gf4bc123cb7-goog