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From:   Zhouyi Zhou <zhouzhouyi@gmail.com>
Date:   Thu, 27 Apr 2023 22:29:32 +0800
Message-ID: <CAABZP2yS5=ZUwEZQ7iHkV0wDm_HgO8K-TeAhyJrZhavzKDa44Q@mail.gmail.com>
Subject: Re: BUG : PowerPC RCU: torture test failed with __stack_chk_fail
To:     Michael Ellerman <mpe@ellerman.id.au>
Cc:     linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        rcu <rcu@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>, lance@osuosl.org,
        "Paul E. McKenney" <paulmck@kernel.org>
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On Thu, Apr 27, 2023 at 10:13=E2=80=AFPM Michael Ellerman <mpe@ellerman.id.=
au> wrote:
>
> Zhouyi Zhou <zhouzhouyi@gmail.com> writes:
> > On Thu, Apr 27, 2023 at 11:09=E2=80=AFAM Michael Ellerman <mpe@ellerman=
.id.au> wrote:
> >>
> >> Zhouyi Zhou <zhouzhouyi@gmail.com> writes:
> >> > On Tue, Apr 25, 2023 at 2:01=E2=80=AFPM Zhouyi Zhou <zhouzhouyi@gmai=
l.com> wrote:
> >> >> On Tue, Apr 25, 2023 at 6:07=E2=80=AFAM Michael Ellerman <mpe@eller=
man.id.au> wrote:
> >> ...
> >> >> >
> >> >> > There's 12.2.0 here:
> >> >> >   https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x=
86_64/12.2.0/
> >> >> >   https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/p=
pc64le/12.2.0/
> >>
> >> > powerpc64le-linux-gnu-gcc-12 cross compiler on my Ubuntu 22.04 does
> >> > not seem to have that issue as gcc-10 does
> >>
> >> OK. So so far it's only that GCC 10 that shows the problem.
> >>
> >> If you have time, you could use some of the other versions to narrow
> >> down which versions show the bug:
> >>
> >>   https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/ppc64l=
e/
> >>
> >> There's an 11.0, 11.1 and 11.3 there, as well as 9.5 and so on.
> > GCC test results (Tested on PPC VM of Open Source Lab of Oregon State
> > University)
> > gcc 9.4 (ubuntu native):          positive, show bug
> > gcc 9.5 (download form [1]):   positive, show bug
> > gcc 10.1 (download from [1]): positive, show bug
> > gcc 10.3 (download from [1]): positive, show bug
> > gcc 10.4 (download from [1]): positive, show bug
> >
> > gcc 11.0 (download from [1]): negative, no bug
> > gcc 11.1 (download from [1]): negative, no bug
> > gcc 11.3 (download from [1]): negative, no bug
> > gcc 12.1 (download from [1]): negative, no bug
> > gcc 12.2 (download from [1]): negative, no bug
>
> Awesome work.
Thank you for your encouragement ;-) ;-)
>
> How are you testing for presence/absence of the bug? By running your
> test and seeing if it crashes, or by looking at the generated code?
Both
I use gdb ./vmlinux; gdb)disassemble srcu_gp_start_if_needed to look
up the generated assembly code
and
I use [1] to see if it crashes, if there is a bug, it always crashes
very quickly (within 3 minutes)
[1] http://140.211.169.189/0425/whilebash.sh

Cheers
>
> cheers