Re: [Valgrind-users] how to generate core file on invalid reads/writes?

[Tomas V. <tv...@fu...>]

On 02/19/2018 11:14 PM, John Reiser wrote:
>> Is there a way to get core when valgrind on invalid access? Am I 
>> missing something?
> 
> If you are running valgrind interactively and valgrind reports an error,
> then one of the error options is to invoke gdb.  Gdb has a command:
>     generate-core-file <filename>
> See the gdb manual which is available online in html.
> 

Interesting. Shame on me for not knowing about the gdbserver thing!

I wonder what exactly does "interactively" mean here. I'm running it as 
part of an automated regression test suite that starts postgres, and 
executes a bunch of SQL scripts on it.

If I understand the docs correctly, this qualifies as interactive. I'll 
try tweaking the scripts tomorrow to use the --vgdb options.

> If you start valgrind with the option  --vgdb-error=<number>
> then you have a gdbserver process which provides *much better*
> service than attaching gdb only at the point of error.
> See the valgrind manual, or "valgrind --help" for a synopsis.
> 
> In either case the core file will include the pieces of valgrind
> which are running in the same process [and address space]
> as "your" program.  So you might become confused while separating
> what is "your" program from what is valgrind.
> 
> For practical purposes (shortest time to finding and fixing
> the "first" error) it often is best to use the --vgdb-error=<number>
> invocation, perhaps with --track-origins=yes.  And yes, this
> means you are allowed to [you must] watch and help.
> 

I don't follow. Watch and help with what?


regards
Tomas