Re: [PATCH] [PATCH v4] lib/ethdev: fix segfault in secondary process by validating dev_private pointer

[Khadem Ullah <14pwcse1224@uetpeshawar.edu.pk>]

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Hi Vipin,

These crashes are specific to the testpmd primary and testpmd
secondary application.
Please check
https://patches.dpdk.org/project/dpdk/patch/20250804113322.53650-1-14pwcse1224@uetpeshawar.edu.pk/
The details are provided over there.

Regards,
Khadem

On Mon, Aug 11, 2025 at 3:19 PM Varghese, Vipin <Vipin.Varghese@amd.com>
wrote:

> [Public]
>
> Snipped
>
> > > Since somehow the email are split it is difficult to see the indexing
> > >
> > > >
> > > > Caution: This message originated from an External Source. Use proper
> > > > caution when opening attachments, clicking links, or responding.
> > > >
> > > >
> > > > Hi Stephen,
> > > >
> > > > Many thanks for diving deeper into the issue and sharing the
> insights.
> > > >
> > > > I agree. given that the primary tears down all the devices on exit,
> > > > the secondary is left with dangling pointers and inconsistent state.
> > >
> > > Secondary if PMD should not be attempting to cleanup (especially for
> ethdev_ptr
> > shared from primary) I agree to that.
> > > But should not be covered in library or PMD. While cleanup for other
> > > needs to be done properly
> > >
> > >  Without a mechanism to notify or synchronize that teardown,
> > >
> > > You already have health check added in the code for identify if primay
> is still alive
> > or not..
> > > There used to be MP thread spawned which actually piggy back the
> > > communication. Is this broken? Can you please point to git
> >
> > There is no easy way to handle the case where primary crashes; leaving
> > secondary process with pointers to dead data.
>
> Thank you for sharing, but as shared the other threads (this topic has 3),
> the reason for the patch is because once the primary is dead it causes
> secondary to crash (segment fault).
>
> As shared in earlier email at least till 22.11 LTS and 23.03 (as it was my
> last testing with multi-process) I did not encounter these.
>
> @Khadem Ullah can you please share which version of DPDK you are noticing
> this failure?
>


-- 
Engr. Khadem Ullah,
Software Engineer,
Dreambig Semiconductor Inc
https://dreambigsemi.com/

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