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From:   Doug Anderson <dianders@chromium.org>
Date:   Thu, 14 Nov 2019 08:10:56 -0800
Message-ID: <CAD=FV=Xkxm-eTXmU9s+Bu+biLmjkioVqmHZEBVguZ85cCQywog@mail.gmail.com>
Subject: Re: [PATCH 1/5] MIPS: kdb: Remove old workaround for backtracing on
 other CPUs
To:     Daniel Thompson <daniel.thompson@linaro.org>
Cc:     Paul Burton <paul.burton@mips.com>,
        Jason Wessel <jason.wessel@windriver.com>,
        qiaochong <qiaochong@loongson.cn>,
        kgdb-bugreport@lists.sourceforge.net,
        Ralf Baechle <ralf@linux-mips.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        James Hogan <jhogan@kernel.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-mips <linux-mips@vger.kernel.org>,
        =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= <f4bug@amsat.org>,
        Serge Semin <fancer.lancer@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>
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Hi,

On Thu, Nov 14, 2019 at 2:51 AM Daniel Thompson
<daniel.thompson@linaro.org> wrote:
>
> On Sat, Nov 09, 2019 at 11:16:40AM -0800, Douglas Anderson wrote:
> > As of commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs
> > that aren't the master") we no longer need any special case for doing
> > stack dumps on CPUs that are not the kdb master.  Let's remove.
> >
> > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > ---
> > I have no way to test this personally, so hopefully someone who uses
> > kdb/kgdb on MIPS can.
>
> I took this as a hint to add mips support to kgdbtest ;-)
>
> Support is added and working well. Unfortunately lack of familiarity
> with mips means I have not yet figured out which mips defconfig gives
> us working SMP (and what the corresponding qemu invocation should be).

Nice!


> I think that means I still can't (quite) exercise this code fully.
> The most appropriate test is bta on an SMP system, right?

Yeah, or at least "btc".


> > Ideally this patch should be Acked by MIPS folks and then land through
> > the kdb/kgdb tree since the next patch in the series, ("kdb:
> > kdb_current_regs should be private") depends on it.
>
> An Acked-by from a MIPS maintainer would be very welcome. Perhaps
> with a bit of extra work on the above I might be able to provide
> a Tested-by:.
>
> I didn't see anything that particularly bothered me in the patches but
> given we're already at -rc7 I'm inclined to target this patchset for 5.6
> rather than 5.5.

That's fine.  This is all just cleanup stuff so targeting 5.6 is fine.

-Doug