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authorAndrey Konovalov <andreyknvl@google.com>2023-12-19 23:28:51 +0100
committerAndrew Morton <akpm@linux-foundation.org>2023-12-29 11:58:37 -0800
commit9f41c59ae3163690868a32bd77e9e33c3bab555e (patch)
tree1fd4cb6949e3d293a236aa39ad572c6ddac95e07
parentf129c31039283df884913142b0f3797d64d3a9d6 (diff)
kasan: introduce kasan_mempool_unpoison_pages
Introduce and document a new kasan_mempool_unpoison_pages hook to be used by the mempool code instead of kasan_unpoison_pages. This hook is not functionally different from kasan_unpoison_pages, but using it improves the mempool code readability. Link: https://lkml.kernel.org/r/239bd9af6176f2cc59f5c25893eb36143184daff.1703024586.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Alexander Lobakin <alobakin@pm.me> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Breno Leitao <leitao@debian.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Marco Elver <elver@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--include/linux/kasan.h25
-rw-r--r--mm/kasan/common.c6
2 files changed, 31 insertions, 0 deletions
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index de2a695ad34d..f8ebde384bd7 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -225,6 +225,9 @@ bool __kasan_mempool_poison_pages(struct page *page, unsigned int order,
* This function is similar to kasan_mempool_poison_object() but operates on
* page allocations.
*
+ * Before the poisoned allocation can be reused, it must be unpoisoned via
+ * kasan_mempool_unpoison_pages().
+ *
* Return: true if the allocation can be safely reused; false otherwise.
*/
static __always_inline bool kasan_mempool_poison_pages(struct page *page,
@@ -235,6 +238,27 @@ static __always_inline bool kasan_mempool_poison_pages(struct page *page,
return true;
}
+void __kasan_mempool_unpoison_pages(struct page *page, unsigned int order,
+ unsigned long ip);
+/**
+ * kasan_mempool_unpoison_pages - Unpoison a mempool page allocation.
+ * @page: Pointer to the page allocation.
+ * @order: Order of the allocation.
+ *
+ * This function is intended for kernel subsystems that cache page allocations
+ * to reuse them instead of freeing them back to page_alloc (e.g. mempool).
+ *
+ * This function unpoisons a page allocation that was previously poisoned by
+ * kasan_mempool_poison_pages() without zeroing the allocation's memory. For
+ * the tag-based modes, this function assigns a new tag to the allocation.
+ */
+static __always_inline void kasan_mempool_unpoison_pages(struct page *page,
+ unsigned int order)
+{
+ if (kasan_enabled())
+ __kasan_mempool_unpoison_pages(page, order, _RET_IP_);
+}
+
bool __kasan_mempool_poison_object(void *ptr, unsigned long ip);
/**
* kasan_mempool_poison_object - Check and poison a mempool slab allocation.
@@ -353,6 +377,7 @@ static inline bool kasan_mempool_poison_pages(struct page *page, unsigned int or
{
return true;
}
+static inline void kasan_mempool_unpoison_pages(struct page *page, unsigned int order) {}
static inline bool kasan_mempool_poison_object(void *ptr)
{
return true;
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index b416f4c265a4..7ebc001d0fcd 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -449,6 +449,12 @@ bool __kasan_mempool_poison_pages(struct page *page, unsigned int order,
return true;
}
+void __kasan_mempool_unpoison_pages(struct page *page, unsigned int order,
+ unsigned long ip)
+{
+ __kasan_unpoison_pages(page, order, false);
+}
+
bool __kasan_mempool_poison_object(void *ptr, unsigned long ip)
{
struct folio *folio;