[PATCH v4 07/11] kfence, kmemleak: make KFENCE compatible with KMEMLEAK

Marco Elver
2020-09-29T14:02:25Z

From: Alexander Potapenko <glider@google.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.

Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Co-developed-by: Marco Elver <elver@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Alexander Potapenko <glider@google.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,
--
2.28.0.709.gb0816b6eb0-goog