[PATCH] test/mbuf: fix the forked process segment fault

[Ruifeng Wang]

> -----Original Message-----
> From: Burakov, Anatoly <anatoly.burakov at intel.com>
> Sent: Monday, May 22, 2023 5:24 PM
> To: Ruifeng Wang <Ruifeng.Wang at arm.com>; olivier.matz at 6wind.com
> Cc: dev at dpdk.org; stable at dpdk.org; thomas at monjalon.net; stephen at networkplumber.org; Justin
> He <Justin.He at arm.com>; Honnappa Nagarahalli <Honnappa.Nagarahalli at arm.com>; nd
> <nd at arm.com>
> Subject: Re: [PATCH] test/mbuf: fix the forked process segment fault
> 
> On 5/22/2023 7:01 AM, Ruifeng Wang wrote:
> > Access of any memory in the hugepage shared file-backed area will
> > trigger an unexpected forked child process segment fault. The root
> > cause is DPDK doesn't support fork model [1] (calling rte_eal_init() before fork()).
> > Forked child process can't be treated as a secondary process.
> >
> > Hence fix it by avoiding fork and doing verification in the main process.
> >
> > [1] https://mails.dpdk.org/archives/dev/2018-July/108106.html
> >
> > Fixes: af75078fece3 ("first public release")
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Jia He <justin.he at arm.com>
> > Signed-off-by: Ruifeng Wang <ruifeng.wang at arm.com>
> > ---
> 
> Would this be something that a secondary process-based test could test?
> That's how we test rte_panic() and other calls.

This case validates mbuf. IMO there is no need to do validation in a secondary process.
Unit test for rte_panic() also uses fork() and could have the same issue.

> 
> --
> Thanks,
> Anatoly