From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39179) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1addbd-0003uL-DB for qemu-devel@nongnu.org; Wed, 09 Mar 2016 07:52:50 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1addbZ-0001EB-Dc for qemu-devel@nongnu.org; Wed, 09 Mar 2016 07:52:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58999) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1addbZ-0001E7-8X for qemu-devel@nongnu.org; Wed, 09 Mar 2016 07:52:45 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id BF1D291C17 for ; Wed, 9 Mar 2016 12:52:44 +0000 (UTC) From: Markus Armbruster References: <1457420446-25276-1-git-send-email-peterx@redhat.com> <1457420446-25276-5-git-send-email-peterx@redhat.com> <56DEC3E0.1010404@redhat.com> <20160309050812.GK2377@pxdev.xzpeter.org> <56DFD66F.9030900@redhat.com> <20160309080750.GR2377@pxdev.xzpeter.org> <87ziu86od1.fsf@blackfin.pond.sub.org> <20160309091912.GU2377@pxdev.xzpeter.org> Date: Wed, 09 Mar 2016 13:52:42 +0100 In-Reply-To: <20160309091912.GU2377@pxdev.xzpeter.org> (Peter Xu's message of "Wed, 9 Mar 2016 17:19:12 +0800") Message-ID: <87shzz6cf9.fsf@blackfin.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH 4/8] usb: fix unbounded stack for xhci_dma_write_u32s List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: Paolo Bonzini , qemu-devel@nongnu.org, Gerd Hoffmann Peter Xu writes: > On Wed, Mar 09, 2016 at 09:34:50AM +0100, Markus Armbruster wrote: >> Peter Xu writes: >> > It's dynamically allocated in stack, can we still use ARRAY_SIZE in >> > this case? >> >> ARRAY_SIZE(x) is defined as (sizeof(x) / sizeof((x)[0])). Works when x >> is of array type (variable length array is fine). Screws up when x is >> of *pointer* type. >> >> C99 6.5.3.4: >> >> The sizeof operator yields the size (in bytes) of its operand, which >> may be an expression or the parenthesized name of a type. The size >> is determined from the type of the operand. The result is an >> integer. If the type of the operand is a variable length array >> type, the operand is evaluated; otherwise, the operand is not >> evaluated and the result is an integer constant. > > Good to know it. Thanks! :) > > However, ARRAY_SIZE() still cannot help solving the unbounded stack > issue, right? Measuring the size of the array doesn't change the size of the array :)