Re: debugging a program which spawns multiple children

On Monday, February 12, 2018 08:24:32 PM Simon Marchi wrote:
> On 2018-02-12 08:19 PM, Christian Groessler wrote:
> > Hi,
> > 
> > I'm trying to debug a problem in FreeBSD's "dump" command. The dump 
> > command creates 4 or 5 child processes,
> > and in my use case one of them gets a SIGSEGV.
> > 
> > Is it possible to monitor all spawned processes simultaneously? I'm 
> > currently using gdb version 7.12.1 from the FreeBSD ports.
> > I would have to problem to use a newer version of gdb and compile it 
> > locally.
> > 
> > regards,
> > chris
> > 
> 
> Hi Christian,
> 
> If GDB for FreeBSD supports it, you can keep debugging the parent process as
> well as child processes by using "set detach-on-fork off".  John (in CC) may
> give more info about the support for multi process debugging with FreeBSD.

GDB 7.12.1 from ports should support fork following as Simon noted, but that
does only work on FreeBSD versions 9.1 and later.

> You might want to read more about the "all-stop" vs "non-stop" modes in the GDB
> documentation and their related settings.

The FreeBSD native target only supports "all-stop" mode currently.

-- 
John Baldwin