From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.9]:40536 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751387AbcJQMIq (ORCPT ); Mon, 17 Oct 2016 08:08:46 -0400 Date: Mon, 17 Oct 2016 05:08:43 -0700 From: Christoph Hellwig Subject: Re: [PATCH] xfs: Fix uninitialized variable in xfs_reflink_reserve_cow_range() Message-ID: <20161017120843.GA9906@infradead.org> References: <1476699404-5977-1-git-send-email-geert@linux-m68k.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1476699404-5977-1-git-send-email-geert@linux-m68k.org> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Geert Uytterhoeven Cc: Dave Chinner , "Darrick J. Wong" , linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org On Mon, Oct 17, 2016 at 12:16:44PM +0200, Geert Uytterhoeven wrote: > with gcc 4.1.2: > > fs/xfs/xfs_reflink.c: In function ‘xfs_reflink_reserve_cow_range’: > fs/xfs/xfs_reflink.c:327: warning: ‘error’ may be used uninitialized in this function > > Indeed, if "count" is zero, the function will return an uninitialized > error value. > > While "count" is unlikely to be zero, this function is called through > the public iomap API. Hence fix this by preinitializing error to zero. The iomap API should never call in with a zero count, but I think the initialization is a fine safety net anyway: Reviewed-by: Christoph Hellwig Btw, what compiler did you get this from? I haven't seen it, but then again I recently missed a lot of initializers without compiler warnings, so either something changed in the Debian stable gcc or our build system recently..