From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 87A991FB7 for ; Fri, 25 Mar 2022 01:13:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5196CC340EE; Fri, 25 Mar 2022 01:13:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648170784; bh=sBga4iICZt57zQq9x4WZawmwLtWQKl78sRfaOI+sIYI=; h=Date:To:From:In-Reply-To:Subject:From; b=wJcc2VQ5MeS2QdDxJu0jRgQhntVPnzXIhQ3A3GUy0bQQ+nNrrzYz+mHQSWV7s2FWu z0qNpGGqFAB95OM7MEaOCyf1E7xh6GEHIGIjt3Zd7I7DaCSY1K6Och6l9jpfTRIKGE VJgKZOZXM4uBjId59OVNQV5lDnIlZrHJ0CO7RY6U= Date: Thu, 24 Mar 2022 18:13:03 -0700 To: ryabinin.a.a@gmail.com,glider@google.com,elver@google.com,dvyukov@google.com,andreyknvl@google.com,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220324180758.96b1ac7e17675d6bc474485e@linux-foundation.org> Subject: [patch 090/114] kasan: add comment about UACCESS regions to kasan_report Message-Id: <20220325011304.5196CC340EE@smtp.kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Andrey Konovalov Subject: kasan: add comment about UACCESS regions to kasan_report Add a comment explaining why kasan_report() is the only reporting function that uses user_access_save/restore(). Link: https://lkml.kernel.org/r/1201ca3c2be42c7bd077c53d2e46f4a51dd1476a.1646237226.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Marco Elver Signed-off-by: Andrew Morton --- mm/kasan/report.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/mm/kasan/report.c~kasan-add-comment-about-uaccess-regions-to-kasan_report +++ a/mm/kasan/report.c @@ -430,6 +430,11 @@ void kasan_report_invalid_free(void *ptr end_report(&flags, ptr); } +/* + * kasan_report() is the only reporting function that uses + * user_access_save/restore(): kasan_report_invalid_free() cannot be called + * from a UACCESS region, and kasan_report_async() is not used on x86. + */ bool kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip) { _