From nobody Fri Dec 19 14:09:39 2025 Received: from out-176.mta0.migadu.com (out-176.mta0.migadu.com [91.218.175.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBE163D0C1 for ; Tue, 19 Dec 2023 22:30:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="qKyzmQgF" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1703025017; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uNoAVP0QdjYefiRU2LrZ1wqxo2WmCMSn1BBV5oc4/p4=; b=qKyzmQgFg/Y7DFx/QocHdWjJrVPMWCP48LD0cbTxo/AvGFiyJYN91o7BgFE+N8U+w/yHzN C6OjPdLT2mHcpxPkyqBEu2zYClKYdujcJMMPKEyXb1+/NggG2ze+zsPE+2stPIX/Yx9tta GpLx/JGbzJYPzm4QqujIB6NjsTUMg1k= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Evgenii Stepanov , Breno Leitao , Alexander Lobakin , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH mm 06/21] kasan: introduce kasan_mempool_poison_pages Date: Tue, 19 Dec 2023 23:28:50 +0100 Message-Id: <88dc7340cce28249abf789f6e0c792c317df9ba5.1703024586.git.andreyknvl@google.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" From: Andrey Konovalov Introduce and document a kasan_mempool_poison_pages hook to be used by the mempool code instead of kasan_poison_pages. Compated to kasan_poison_pages, the new hook: 1. For the tag-based modes, skips checking and poisoning allocations that were not tagged due to sampling. 2. Checks for double-free and invalid-free bugs. In the future, kasan_poison_pages can also be updated to handle #2, but this is out-of-scope of this series. Signed-off-by: Andrey Konovalov --- include/linux/kasan.h | 27 +++++++++++++++++++++++++++ mm/kasan/common.c | 23 +++++++++++++++++++++++ 2 files changed, 50 insertions(+) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index c5fe303bc1c2..de2a695ad34d 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -212,6 +212,29 @@ static __always_inline void * __must_check kasan_kreal= loc(const void *object, return (void *)object; } =20 +bool __kasan_mempool_poison_pages(struct page *page, unsigned int order, + unsigned long ip); +/** + * kasan_mempool_poison_pages - Check and poison 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 allocat= ions + * to reuse them instead of freeing them back to page_alloc (e.g. mempool). + * + * This function is similar to kasan_mempool_poison_object() but operates = on + * page allocations. + * + * Return: true if the allocation can be safely reused; false otherwise. + */ +static __always_inline bool kasan_mempool_poison_pages(struct page *page, + unsigned int order) +{ + if (kasan_enabled()) + return __kasan_mempool_poison_pages(page, order, _RET_IP_); + return true; +} + bool __kasan_mempool_poison_object(void *ptr, unsigned long ip); /** * kasan_mempool_poison_object - Check and poison a mempool slab allocatio= n. @@ -326,6 +349,10 @@ static inline void *kasan_krealloc(const void *object,= size_t new_size, { return (void *)object; } +static inline bool kasan_mempool_poison_pages(struct page *page, unsigned = int order) +{ + return true; +} static inline bool kasan_mempool_poison_object(void *ptr) { return true; diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 4b85d35bb8ab..b416f4c265a4 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -426,6 +426,29 @@ void * __must_check __kasan_krealloc(const void *objec= t, size_t size, gfp_t flag return ____kasan_kmalloc(slab->slab_cache, object, size, flags); } =20 +bool __kasan_mempool_poison_pages(struct page *page, unsigned int order, + unsigned long ip) +{ + unsigned long *ptr; + + if (unlikely(PageHighMem(page))) + return true; + + /* Bail out if allocation was excluded due to sampling. */ + if (!IS_ENABLED(CONFIG_KASAN_GENERIC) && + page_kasan_tag(page) =3D=3D KASAN_TAG_KERNEL) + return true; + + ptr =3D page_address(page); + + if (check_page_allocation(ptr, ip)) + return false; + + kasan_poison(ptr, PAGE_SIZE << order, KASAN_PAGE_FREE, false); + + return true; +} + bool __kasan_mempool_poison_object(void *ptr, unsigned long ip) { struct folio *folio; --=20 2.25.1