[patch 023/262] kasan: generic: introduce kasan_record_aux_stack_noalloc()

Andrew Morton
2021-11-05T20:35:49Z

From: Marco Elver <elver@google.com>
Subject: kasan: generic: introduce kasan_record_aux_stack_noalloc()

Introduce a variant of kasan_record_aux_stack() that does not do any
memory allocation through stackdepot. This will permit using it in
contexts that cannot allocate any memory.

Link: https://lkml.kernel.org/r/20210913112609.2651084-6-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Tested-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Taras Madan <tarasmadan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/linux/kasan.h | 2 ++
mm/kasan/generic.c | 14 ++++++++++++--
2 files changed, 14 insertions(+), 2 deletions(-)

--- a/include/linux/kasan.h~kasan-generic-introduce-kasan_record_aux_stack_noalloc
+++ a/include/linux/kasan.h
@@ -370,12 +370,14 @@ static inline void kasan_unpoison_task_s
void kasan_cache_shrink(struct kmem_cache *cache);
void kasan_cache_shutdown(struct kmem_cache *cache);
void kasan_record_aux_stack(void *ptr);
+void kasan_record_aux_stack_noalloc(void *ptr);

#else /* CONFIG_KASAN_GENERIC */

static inline void kasan_cache_shrink(struct kmem_cache *cache) {}
static inline void kasan_cache_shutdown(struct kmem_cache *cache) {}
static inline void kasan_record_aux_stack(void *ptr) {}
+static inline void kasan_record_aux_stack_noalloc(void *ptr) {}

#endif /* CONFIG_KASAN_GENERIC */

--- a/mm/kasan/generic.c~kasan-generic-introduce-kasan_record_aux_stack_noalloc
+++ a/mm/kasan/generic.c
@@ -328,7 +328,7 @@ DEFINE_ASAN_SET_SHADOW(f3);
DEFINE_ASAN_SET_SHADOW(f5);
DEFINE_ASAN_SET_SHADOW(f8);

-void kasan_record_aux_stack(void *addr)
+static void __kasan_record_aux_stack(void *addr, bool can_alloc)
{
struct page *page = kasan_addr_to_page(addr);
struct kmem_cache *cache;
@@ -345,7 +345,17 @@ void kasan_record_aux_stack(void *addr)
return;

alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0];
- alloc_meta->aux_stack[0] = kasan_save_stack(GFP_NOWAIT, true);
+ alloc_meta->aux_stack[0] = kasan_save_stack(GFP_NOWAIT, can_alloc);
+}
+
+void kasan_record_aux_stack(void *addr)
+{
+ return __kasan_record_aux_stack(addr, true);
+}
+
+void kasan_record_aux_stack_noalloc(void *addr)
+{
+ return __kasan_record_aux_stack(addr, false);
}

void kasan_set_free_info(struct kmem_cache *cache,
_