Re: [PATCH 1/1 v2]: coredump: use current->group_leader->comm instead of current->comm

[Oleg Nesterov <oleg@redhat.com>]

On 09/02, Earl Chew wrote:
>
> Oleg,
>
> >> The patterns %n or %N are the same as %e and %E except that they
> >> use current->group_leader->comm instead of current->comm.
> >
> > I simply do not know what is better. Alan has a point imho, "might
> > break stuff" is true.
> >
> > OTOH, %p always reports tgid, not tid...
>
> Which speaks partly to my notion of "consistency".

That is why I mentioned it with "otoh" ;)

> I viewed my original change as more "consistent" because it
> yielded the attribute alluded to in the documentation --- the
> same value for all threads in the one process:
>
> 	- Consistent with the documentation
> 	- Consistent with respect to process name (as opposed to thread name)
>
> >> A core dump can be triggered from any task in a group,
> >
> > Indeed. The important case is the private/synchronous signals like
> > SIGSEGV, you can see the name of the thread which triggered the crash.
>
> While that is true, it doesn't seem to have been the original intent as
> per the %e documentation.

May be. May be not. I do not know.

> Should get_mm_exe_file() just use current->group_leader->comm since it's
> meant to be process specific anyway,

Probably. Although group_leader->comm is thread specific too, but
at least we do not use the "random" thread. My only point was, imho
this doesn't deserve another option.

> and there isn't an existing code base
> for %E ?

Who knows? But once again, we use ->comm in the very unlikely case.



And let me repeat just in case. I do not argue, I agree either way.

Oleg.