linux-kernel - Re: [PATCH] mm/page_alloc: Work around a pahole limitation with zero-sized struct pagesets

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAEf4BzbbQfwUERObV4EQ4fTx3auKZm_CyoidWK7hWAK32wFZ3A@mail.gmail.com>
Date:   Wed, 26 May 2021 11:41:41 -0700
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     Mel Gorman <mgorman@...hsingularity.net>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Michal Suchanek <msuchanek@...e.de>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        open list <linux-kernel@...r.kernel.org>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Hritik Vijay <hritikxx8@...il.com>, bpf <bpf@...r.kernel.org>,
        Linux-Net <netdev@...r.kernel.org>, Linux-MM <linux-mm@...ck.org>
Subject: Re: [PATCH] mm/page_alloc: Work around a pahole limitation with
 zero-sized struct pagesets

On Wed, May 26, 2021 at 11:13 AM Mel Gorman <mgorman@...hsingularity.net> wrote:
>
> On Wed, May 26, 2021 at 09:57:31AM -0700, Andrii Nakryiko wrote:
> > > This patch checks for older versions of pahole and forces struct pagesets
> > > to be non-zero sized as a workaround when CONFIG_DEBUG_INFO_BTF is set. A
> > > warning is omitted so that distributions can update pahole when 1.22
> >
> > s/omitted/emitted/ ?
> >
>
> Yes.
>
> > > is released.
> > >
> > > Reported-by: Michal Suchanek <msuchanek@...e.de>
> > > Reported-by: Hritik Vijay <hritikxx8@...il.com>
> > > Debugged-by: Andrii Nakryiko <andrii.nakryiko@...il.com>
> > > Signed-off-by: Mel Gorman <mgorman@...hsingularity.net>
> > > ---
> >
> > Looks good! I verified that this does fix the issue on the latest
> > linux-next tree, thanks!
> >
>
> Excellent
>
> > One question, should
> >
> > Fixes: 5716a627517d ("mm/page_alloc: convert per-cpu list protection
> > to local_lock")
> >
> > be added to facilitate backporting?
> >
>
> The git commit is not stable because the patch "mm/page_alloc: convert
> per-cpu list protection to local_lock" is in Andrew's mmotm tree which is

Oh, I didn't know about this instability.

> quilt based. I decided not to treat the patch as a fix because the patch is
> not wrong as such, it's a limitation of an external tool.  However, I would
> expect both the problematic patch and the BTF workaround to go in during
> the same merge window so backports to -stable should not be required.

Yep, makes sense.

>
> > Either way:
> >
> > Acked-by: Andrii Nakryiko <andrii@...nel.org>
> > Tested-by: Andrii Nakryiko <andrii@...nel.org>
> >
>
> Thanks!
>
> --
> Mel Gorman
> SUSE Labs