netdev - Re: [PATCH net 2/2] bnxt_en: Fix NULL ptr dereference crash in bnxt_fw_reset

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Message-ID: <CACKFLimwdvnCWw6qG1ReCRW3XgSS1UEwNa=cuPFZKeb+VG2hZQ@mail.gmail.com>
Date:   Sun, 6 Sep 2020 20:48:04 -0700
From:   Michael Chan <michael.chan@...adcom.com>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     David Miller <davem@...emloft.net>,
        Netdev <netdev@...r.kernel.org>,
        Vasundhara Volam <vasundhara-v.volam@...adcom.com>
Subject: Re: [PATCH net 2/2] bnxt_en: Fix NULL ptr dereference crash in bnxt_fw_reset_task()

On Sun, Sep 6, 2020 at 8:13 PM Jakub Kicinski <kuba@...nel.org> wrote:
>
> On Sun, 6 Sep 2020 15:07:02 -0700 Michael Chan wrote:
> > On Sun, Sep 6, 2020 at 12:25 PM Jakub Kicinski <kuba@...nel.org> wrote:
> > >
> > > devlink can itself scheduler a recovery via:
> > >
> > >   bnxt_fw_fatal_recover() -> bnxt_fw_reset()
> > >
> >
> > Yes, this is how it is initiated when we call devlink_health_report()
> > to report the error condition.  From bnxt_fw_reset(), we use a
> > workqueue because we have to go through many states, requiring
> > sleeping/polling to transition through the states.
> >
> > > no? Maybe don't make the devlink recovery path need to go via a
> > > workqueue?
> >
> > Current implementation is going through a work queue.
>
> What I'm saying is the code looks like this after this patch:
>
> +       clear_bit(BNXT_STATE_IN_FW_RESET, &bp->state);
> +       bnxt_cancel_sp_work(bp);
> +       bp->sp_event = 0;
> +
>         bnxt_dl_fw_reporters_destroy(bp, true);
>
> It cancels the work, _then_ destroys the reporter. But I think the
> reported can be used to schedule a recovery from command line. So the
> work may get re-scheduled after it has been canceled.

bnxt_en does not support recovery from the command line.  We return
-EOPNOTSUPP when it comes from the command line.

Recovery has to be triggered from a firmware reported error or a
driver detected error.