On Fri, Dec 2, 2022 at 7:00 PM Mike Pattrick <[email protected]> wrote:
> > >>>> Did you consider madvise()?
> > >>>>
> > >>>>         MADV_DONTDUMP (since Linux 3.4)
> > >>>>                Exclude from a core dump those pages in the range
> > >>>> specified by addr and length.  This is useful in applications that
> > >>>> have large areas of memory that are known not to be useful in a core
> > >>>> dump.  The effect of  MADV_DONT‐
> > >>>>                DUMP takes precedence over the bit mask that is set via
> > >>>> the /proc/[pid]/coredump_filter file (see core(5)).
> > >>>>
> > >>>>         MADV_DODUMP (since Linux 3.4)
> > >>>>                Undo the effect of an earlier MADV_DONTDUMP.
> > >>>
> > I guess, while DONTDUMP calls are mainly harmless, the explicit DODUMP
> > will override whatever user had in their global configuration.  Meaning
> > every DPDK application with vhost ports will start dumping some of the
> > guest pages with no actual ability to turn that off.
>
> I initially thought it would work that way, but the DODUMP flag just
> disables the DONTDUMP flag.
>
> https://github.com/torvalds/linux/blob/master/mm/madvise.c#L1055
> https://github.com/torvalds/linux/blob/master/fs/coredump.c#L1033
>

Glad to read that the manual tells the same story than the kernel code :-).


-- 
David Marchand

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