From: Sergei Trofimovich <slyfox@gentoo.org>
To: Andrey Konovalov <andreyknvl@gmail.com>
Cc: David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH] mm: page_alloc: ignore init_on_free=1 for page alloc
Date: Fri, 26 Mar 2021 16:42:04 +0000 [thread overview]
Message-ID: <20210326164204.29da5808@sf> (raw)
In-Reply-To: <CA+fCnZeC8AWearU9CQaYrFM-ZCUaQpX1e7vBkRMNtqqf_=ucGA@mail.gmail.com>
On Fri, 26 Mar 2021 16:00:34 +0100
Andrey Konovalov <andreyknvl@gmail.com> wrote:
> On Fri, Mar 26, 2021 at 2:49 PM David Hildenbrand <david@redhat.com> wrote:
> >
> > > I observed use of poisoned pages as the crash on ia64 booted with
> > > init_on_free=1 init_on_alloc=1 (CONFIG_PAGE_POISONING=y config).
> > > There pmd page contained 0xaaaaaaaa poison pages and led to early crash.
> > >
> > > The change drops the assumption that init_on_free=1 guarantees free
> > > pages to contain zeros.
> > >
> > > Alternative would be to make interaction between runtime poisoning and
> > > sanitizing options and build-time debug flags like CONFIG_PAGE_POISONING
> > > more coherent. I took the simpler path.
> > >
> >
> > I thought latest work be Vlastimil tried to tackle that. To me, it feels
> > like page_poison=on and init_on_free=1 should bail out and disable one
> > of both things. Having both at the same time doesn't sound helpful.
>
> This is exactly how it works, see init_mem_debugging_and_hardening().
>
> Sergei, could you elaborate more on what kind of crash this patch is
> trying to fix? Where does it happen and why?
Yeah, I see I misinterpreted page_poison=on handling and misled you all.
Something else poisons a page when it should have not. I'll answer in more
detail to Vlastimil's email upthread and will provide more detail of the
unexpected poisoning I see.
--
Sergei
next prev parent reply other threads:[~2021-03-26 16:43 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 11:26 [PATCH] mm: page_alloc: ignore init_on_free=1 for page alloc Sergei Trofimovich
2021-03-26 13:48 ` David Hildenbrand
2021-03-26 15:00 ` Andrey Konovalov
2021-03-26 15:00 ` Andrey Konovalov
2021-03-26 16:42 ` Sergei Trofimovich [this message]
2021-03-29 12:10 ` Vlastimil Babka
2021-03-29 22:00 ` Andrey Konovalov
2021-03-29 22:00 ` Andrey Konovalov
2021-03-29 22:07 ` Vlastimil Babka
2021-03-30 14:48 ` Andrey Konovalov
2021-03-30 14:48 ` Andrey Konovalov
2021-03-26 14:17 ` Vlastimil Babka
2021-03-26 17:25 ` Sergei Trofimovich
2021-03-27 18:03 ` Sergei Trofimovich
2021-03-27 18:21 ` [PATCH v2] mm: page_alloc: ignore init_on_free=1 for debug_pagealloc=1 Sergei Trofimovich
2021-03-29 9:23 ` David Hildenbrand
2021-03-29 11:59 ` Vlastimil Babka
2021-03-29 22:25 ` [PATCH v3] " Sergei Trofimovich
2021-03-30 8:39 ` David Hildenbrand
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210326164204.29da5808@sf \
--to=slyfox@gentoo.org \
--cc=akpm@linux-foundation.org \
--cc=andreyknvl@gmail.com \
--cc=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.