From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14599 invoked by alias); 15 Jul 2005 21:30:04 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 14529 invoked by uid 22791); 15 Jul 2005 21:29:56 -0000 Received: from everest.cs.wisc.edu (HELO everest.cs.wisc.edu) (128.105.166.17) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Fri, 15 Jul 2005 21:29:56 +0000 Received: from everest.cs.wisc.edu (localhost [127.0.0.1]) by everest.cs.wisc.edu (8.13.1/8.13.1) with ESMTP id j6FLTsYn008747; Fri, 15 Jul 2005 16:29:54 -0500 Received: (from xu@localhost) by everest.cs.wisc.edu (8.13.1/8.13.1/Submit) id j6FLTrVW008746; Fri, 15 Jul 2005 16:29:53 -0500 Date: Fri, 15 Jul 2005 21:30:00 -0000 From: "Min Xu (Hsu)" To: Larry Martell Cc: gdb@sources.redhat.com Subject: Re: gdb runs multi-threaded with non-threaded app and gets SEGV Message-ID: <20050715212943.GA7686@cs.wisc.edu> References: <1121456545.7681.5.camel@localhost.localdomain> <20050715210258.22352.qmail@web52009.mail.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050715210258.22352.qmail@web52009.mail.yahoo.com> User-Agent: Mutt/1.5.5.1i X-SW-Source: 2005-07/txt/msg00184.txt.bz2 Larry, How about you run the program and let the program pass the lib call without using GDB. And spin there until gdb is attached? -Min On Fri, 15 Jul 2005 Larry Martell wrote : > --- Ramana Radhakrishnan > wrote: > > On Fri, 2005-07-15 at 11:25 -0700, Larry Martell > > wrote: > > > I have a program that has 1 line of code - a call > > to > > > a third party libary function: > > > > > > #include "ni488.h" > > > > > > int main() { > > > int handle = ibdev(0, 7, 0, 10, 1, 0); > > > } > > > > > > That is not enough info for us to help you with . > > Try CVS head or a more > > recent version of gdb and see if that works. > > OK, I've upgraded to gdb 6.3 > > > Whats the version of libc , > > 2.3.3 > > > gcc > > 3.4.1 > > > Also maybe your 3rd party > > library might be multithreaded for all we know. Do a > > ldd on the library if its a .so and check . > > OK, an ldd showed: > > libpthread.so.0 => /lib/tls/libpthread.so.0 > (0x40278000) > > So apparently the 3rd party lib is multithreaded. > > So that answers 1 question. But the more important one > is why I get the SEGV in gdb, but not when I run the > program without gdb? > > Here's the deal - I am developing an app (that is > not getting a SEGV) and I wanted to debug it. When > I ran the app in gdb it got the SEGV on my call to > ibdev. Thinking I probably had a memory corruption > somewhere in my application I ran valgrind on it. > It said the 3rd party lib was attempting to jump > to address 0. Still thinking it was my issue, I > created the single line test program (shown at the > top of this message). And that's where I am now - I > need gdb to get past this call so I can debug my > actaul app. > > Thanks! > -larry > > > > > The program is not multi-threaded nor does not > > link > > > with any multi-threaded libs. It's built like > > this: > > > > > > gcc -g -o nitest nitest.c -lgpibapi > > > > > > If I run the program outside of the debugger it > > does > > > not crash. > > > > > > If I run it from within gdb here's what I get: > > > > > > $ gdb nitest > > > GNU gdb 6.2-2mdk (Mandrakelinux) > > > Copyright 2004 Free Software Foundation, Inc. > > > GDB is free software, covered by the GNU General > > > Public License, and you are > > > welcome to change it and/or distribute copies of > > it > > > under certain conditions. > > > Type "show copying" to see the conditions. > > > There is absolutely no warranty for GDB. Type > > "show > > > warranty" for details. > > > This GDB was configured as > > > "i586-mandrake-linux-gnu"...Using host > > libthread_db > > > library "/lib/tls/libthread_db.so.1". > > > > > > (gdb) start > > > Breakpoint 1 at 0x8048398: file nitest.c, line 4. > > > Starting program: /home/martell/src/nitest2/nitest > > > [Thread debugging using libthread_db enabled] > > > [New Thread 1076484320 (LWP 9873)] > > > [Switching to Thread 1076484320 (LWP 9873)] > > > main () at nitest.c:4 > > > 4 int handle = ibdev(0, 7, 0, 10, 1, > > 0); > > > (gdb) c > > > Continuing. > > > [New Thread 1085078448 (LWP 9876)] > > > [New Thread 1093471152 (LWP 9877)] > > > > > > Program received signal SIGSEGV, Segmentation > > fault. > > > [Switching to Thread 1085078448 (LWP 9876)] > > > 0x4005d609 in ?? () from > > > /usr/local/lib/libgpibapi.so.2 > > > > > > Can anyone tell me why gdb runs this as > > multi-threaded > > > and why I get a SEGV in gdb, but I do not when I > > run > > > it outside of gdb? > > > > > > Thanks! > > > -larry > > > > > > >