From: Thomas Gleixner <tglx@linutronix.de>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Pekka Enberg <penberg@kernel.org>, Linux-MM <linux-mm@kvack.org>
Subject: Re: [patch V4 01/32] mm/slab: Fix broken stack trace storage
Date: Mon, 15 Apr 2019 23:20:42 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1904152318020.1806@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190415161657.2zwboghblj5ducux@treble>
On Mon, 15 Apr 2019, Josh Poimboeuf wrote:
> On Mon, Apr 15, 2019 at 06:07:44PM +0200, Thomas Gleixner wrote:
> > >
> > > Looks like stack_trace.nr_entries isn't initialized? (though this code
> > > gets eventually replaced by a later patch)
> >
> > struct initializer initialized the non mentioned fields to 0, if I'm not
> > totally mistaken.
>
> Hm, it seems you are correct. And I thought I knew C.
:)
> > > Who actually reads this stack trace? I couldn't find a consumer.
> >
> > It's stored directly in the memory pointed to by @addr and that's the freed
> > cache memory. If that is used later (UAF) then the stack trace can be
> > printed to see where it was freed.
>
> Right... but who reads it?
Indeed. I didn't check but I know that I saw that info printed at least a
decade ago. Looks like that debug magic in slab.c has seen major changes
since then.
Thanks,
tglx
next prev parent reply other threads:[~2019-04-15 21:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190414155936.679808307@linutronix.de>
2019-04-14 15:59 ` [patch V3 01/32] mm/slab: Fix broken stack trace storage Thomas Gleixner
2019-04-14 16:16 ` Andy Lutomirski
2019-04-14 16:34 ` Thomas Gleixner
2019-04-15 9:02 ` [patch V4 " Thomas Gleixner
2019-04-15 13:23 ` Josh Poimboeuf
2019-04-15 16:07 ` Thomas Gleixner
2019-04-15 16:16 ` Josh Poimboeuf
2019-04-15 17:05 ` Andy Lutomirski
2019-04-15 21:22 ` Thomas Gleixner
2019-04-16 11:37 ` Vlastimil Babka
2019-04-16 14:10 ` [patch V5 01/32] mm/slab: Remove " Thomas Gleixner
2019-04-16 15:16 ` Vlastimil Babka
2019-04-15 21:20 ` Thomas Gleixner [this message]
2019-04-15 16:21 ` [patch V4 01/32] mm/slab: Fix " Peter Zijlstra
2019-04-15 16:58 ` [patch V3 " Andy Lutomirski
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=alpine.DEB.2.21.1904152318020.1806@nanos.tec.linutronix.de \
--to=tglx@linutronix.de \
--cc=akpm@linux-foundation.org \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=penberg@kernel.org \
--cc=sean.j.christopherson@intel.com \
--cc=x86@kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).