From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <libffi-discuss-return-2201-listarch-libffi-discuss=sources.redhat.com@sourceware.org>
Received: (qmail 12097 invoked by alias); 27 Apr 2015 17:48:35 -0000
Mailing-List: contact libffi-discuss-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <libffi-discuss.sourceware.org>
List-Subscribe: <mailto:libffi-discuss-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/libffi-discuss/>
List-Post: <mailto:libffi-discuss@sourceware.org>
List-Help: <mailto:libffi-discuss-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: libffi-discuss-owner@sourceware.org
Received: (qmail 12044 invoked by uid 89); 27 Apr 2015 17:48:32 -0000
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2
X-HELO: mail-wg0-f41.google.com
Received: from mail-wg0-f41.google.com (HELO mail-wg0-f41.google.com) (74.125.82.41) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Mon, 27 Apr 2015 17:48:31 +0000
Received: by wgin8 with SMTP id n8so124294138wgi.0        for <libffi-discuss@sourceware.org>; Mon, 27 Apr 2015 10:48:29 -0700 (PDT)
X-Received: by 10.180.75.197 with SMTP id e5mr22512384wiw.94.1430156908993; Mon, 27 Apr 2015 10:48:28 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.194.33.135 with HTTP; Mon, 27 Apr 2015 10:48:08 -0700 (PDT)
In-Reply-To: <CAKRnqNL8L77vGkzZrA8Tbcrv8Y3u2J-LCu=r5=bppOVgWSve4A@mail.gmail.com>
References: <CAKRnqNK1D9Wp3uedW62uVk-5FCfzGgDd0xOA2W9qMQeizV1TSw@mail.gmail.com> <553E6D2E.7060403@redhat.com> <CAKRnqNJtEj_VvXNrF=QXteJAwAYmKZ3K1PAxtb35hY43Nr0ezw@mail.gmail.com> <CAKRnqNL8L77vGkzZrA8Tbcrv8Y3u2J-LCu=r5=bppOVgWSve4A@mail.gmail.com>
From: Bruce Korb <bruce.korb@gmail.com>
Date: Mon, 27 Apr 2015 17:48:00 -0000
Message-ID: <CAKRnqN+bNsRvSghdF5trX14SdhmZSh1jOR_eu0bhw5tS9vzpVQ@mail.gmail.com>
Subject: Re: pass by value and also snprintf()
To: Richard Henderson <rth@redhat.com>
Cc: libffi-discuss@sourceware.org
Content-Type: text/plain; charset=UTF-8
X-SW-Source: 2015/txt/msg00068.txt.bz2

The GDB result (using snprintf this time):

(gdb)
37              if (ffi_prep_cif_var(&cif, FFI_DEFAULT_ABI, 3, 5,
(gdb)
41                      ffi_call(&cif, fn, &ret_val, values);
(gdb)

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff787f562 in vsnprintf () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0  0x00007ffff787f562 in vsnprintf () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007ffff7861532 in snprintf () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007ffff7bd7adc in ffi_call_unix64 () from
/usr/lib/x86_64-linux-gnu/libffi.so.6
#3  0x00007ffff7bd740c in ffi_call () from /usr/lib/x86_64-linux-gnu/libffi.so.6
#4  0x0000000000400ac0 in main (argc=1, argv=0x7fffffffe488) at ffi-test.c:41


If I link against the -O0 -ggdb3 version of libffi, what can I do to
help diagnose?