From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
paulus@samba.org, cjashfor@linux.vnet.ibm.com,
fweisbec@gmail.com, linux-kernel@vger.kernel.org,
"James E.J. Bottomley" <jejb@parisc-linux.org>,
Jan Blunck <jblunck@suse.de>
Subject: Re: [RFC 0/5] kernel: backtrace unwind support
Date: Tue, 14 Feb 2012 13:22:24 +1100 [thread overview]
Message-ID: <1329186144.2534.26.camel@pasglop> (raw)
In-Reply-To: <CA+55aFzhenNyPUzAVpXhuxfVpAuowY+OcvPGyfg8_o9NN4SDtw@mail.gmail.com>
On Fri, 2012-02-10 at 12:37 -0800, Linus Torvalds wrote:
> On Fri, Feb 10, 2012 at 12:18 PM, Jiri Olsa <jolsa@redhat.com> wrote:
> >
> > yep, looks interesting.. not sure about the mathematical proof though ;)
>
> Well, I can already say what the old code did horribly horribly wrong:
>
> - *all* stack accesses need to go through a validation function, they
> can never *ever* just try to access the stack.
>
> The validation function really needs to really check the full
> range of the stack area, not something random.
>
> - all dwarf information accesses need to similarly validate the
> access, and accept that sometimes the dwarf info is simply missing or
> actively wrong.
In addition it should all go through something like
copy_from_user_inatomic(), ie, all access to that stuff should have
built-in fault recovery without triggering high level page faults, stack
expansion etc...
Cheers,
Ben.
next prev parent reply other threads:[~2012-02-14 2:23 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-10 11:25 [RFC 0/5] kernel: backtrace unwind support Jiri Olsa
2012-02-10 11:25 ` [PATCH 1/5] unwind, kconfig: Adding UNWIND* options Jiri Olsa
2012-02-10 11:25 ` [PATCH 2/5] unwind, x86: Generate exception frames data for UNWIND_EH_FRAME option Jiri Olsa
2012-02-10 11:25 ` [PATCH 3/5] unwind, dwarf: Add dwarf unwind support Jiri Olsa
2012-02-10 11:25 ` [PATCH 4/5] unwind, api: Add unwind interface and implementation for x86_64 Jiri Olsa
2012-02-10 11:25 ` [PATCH 5/5] unwind, test: Add backtrace unwind test code Jiri Olsa
2012-02-10 17:43 ` [RFC 0/5] kernel: backtrace unwind support Peter Zijlstra
2012-02-10 18:59 ` Linus Torvalds
2012-02-10 19:27 ` Arnaldo Carvalho de Melo
2012-02-10 19:32 ` Linus Torvalds
2012-02-10 19:39 ` Arnaldo Carvalho de Melo
2012-02-10 19:42 ` Arnaldo Carvalho de Melo
2012-02-10 19:44 ` Ingo Molnar
2012-02-10 20:18 ` Jiri Olsa
2012-02-10 20:37 ` Linus Torvalds
2012-02-14 2:22 ` Benjamin Herrenschmidt [this message]
2012-02-11 14:38 ` Ingo Molnar
2012-02-11 23:36 ` Jiri Olsa
2012-02-11 3:25 ` Frederic Weisbecker
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