From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:56563) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RxHnY-0004Bg-MX for qemu-devel@nongnu.org; Tue, 14 Feb 2012 07:48:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RxHnO-0000Fw-Vn for qemu-devel@nongnu.org; Tue, 14 Feb 2012 07:47:56 -0500 Received: from mail-pw0-f45.google.com ([209.85.160.45]:52234) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RxHnO-0000Fm-Po for qemu-devel@nongnu.org; Tue, 14 Feb 2012 07:47:46 -0500 Received: by pbbro12 with SMTP id ro12so477019pbb.4 for ; Tue, 14 Feb 2012 04:47:45 -0800 (PST) Message-ID: <4F3A57EF.6000102@codemonkey.ws> Date: Tue, 14 Feb 2012 06:47:43 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <1328884453-1067-1-git-send-email-zwu.kernel@gmail.com> <20120210144115.GI2914@redhat.com> <4F353D75.2050801@weilnetz.de> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] oslib: make error handling more reasonable List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Zhi Yong Wu , Stefan Weil , QEMU Developers On 02/13/2012 08:04 AM, Markus Armbruster wrote: > Stefan Weil writes: > >> Am 10.02.2012 16:13, schrieb Zhi Yong Wu: >>> On Fri, Feb 10, 2012 at 10:41 PM, Daniel P. Berrange >>> wrote: >>>> On Fri, Feb 10, 2012 at 10:34:13PM +0800, Zhi Yong Wu wrote: >>>>> From: Zhi Yong Wu >>>>> >>>>> Signed-off-by: Zhi Yong Wu >>>>> --- >>>>> oslib-posix.c | 4 ++-- >>>>> oslib-win32.c | 4 ++-- >>>>> 2 files changed, 4 insertions(+), 4 deletions(-) >>>>> >>>>> diff --git a/oslib-posix.c b/oslib-posix.c >>>>> index b6a3c7f..f978d56 100644 >>>>> --- a/oslib-posix.c >>>>> +++ b/oslib-posix.c >>>>> @@ -80,7 +80,7 @@ void *qemu_oom_check(void *ptr) >>>>> { >>>>> if (ptr == NULL) { >>>>> fprintf(stderr, "Failed to allocate memory: %s\n", >>>>> strerror(errno)); >>>>> - abort(); >>>>> + exit(EXIT_FAILURE); >>>> >>>> exit() will call any atexit()/on_exit() handlers, as well as trying >>>> to flush I/O streams. Any of these actions may require further >>>> memory allocations, which will likely fail, or worse cause this >>>> code to re-enter itself if an atexit() handler calls qemu_malloc >>> Nice, very reasonable. >>>> >>>> The only option other than abort(), is to use _Exit() which >>>> doesn't try to run cleanup handlers. >>> I will try to send out v2 >> >> Could you please explain why calling exit, _Exit or _exit is more >> reasonable than calling abort? >> >> abort can create core dumps or start a debugger which is >> useful for me and maybe other developers, too. > > I consider abort() on OOM somewhat eccentric. abort() is for > programming errors. Resource shortage is an environmental error that is > sometimes (but not always) caused by a programming error. > > I'd rather inconvenience programmers (by making it a little bit harder > to debug programming errors that cause OOM) than confuse users with > inappropriate scary "crashes". OOM is a going to 99% of the time be a bug in QEMU. For the rare exceptions (like a bad -m argument), we should handle those as special cases. Regards, Anthony Liguori >