From: Torsten Duwe <duwe@lst.de>
To: Jiri Kosina <jikos@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>,
Balbir Singh <bsingharora@gmail.com>,
linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org,
rostedt@goodmis.org, kamalesh@linux.vnet.ibm.com,
jeyu@redhat.com, live-patching@vger.kernel.org, mbenes@suse.cz
Subject: Re: [PATCH][v6][RFC] livepatch/ppc: Enable livepatching on powerpc
Date: Wed, 9 Mar 2016 12:16:47 +0100 [thread overview]
Message-ID: <20160309111647.GA27913@lst.de> (raw)
In-Reply-To: <alpine.LNX.2.00.1603091110510.3656@cbobk.fhfr.pm>
On Wed, Mar 09, 2016 at 11:13:05AM +0100, Jiri Kosina wrote:
> On Wed, 9 Mar 2016, Torsten Duwe wrote:
> > was my first choice. Arguments on the stack? I thought we'll deal with them
> > once we get there (e.g. _really_ need to patch a varargs function or one
> > with a silly signature).
>
> Well, the problem is, once such need arises, it's too late already.
No, not if it's documented.
> You need to be able to patch the kernels which are already out there,
> running on machines potentially for ages once all of a sudden there is a
> CVE for >8args / varargs function.
Then you'd need a solution like I sent out yesterday, with a pre-prologue
caller that pops the extra frame, so the replacement can be more straight-
forward. Or you can just deal with the shifted offsets in the replacement.
I'll try to demonstrate the alternative. That would then be required for
_all_ replacement functions. Or can the live patching framework differentiate
and tell ftrace_caller whether to place a stack frame or not?
Miroslav? Petr? Can we have 2 sorts of replacement functions?
Torsten
next prev parent reply other threads:[~2016-03-09 11:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 6:59 [PATCH][v6][RFC] livepatch/ppc: Enable livepatching on powerpc Balbir Singh
2016-03-09 9:19 ` Torsten Duwe
2016-03-09 9:44 ` Petr Mladek
2016-03-09 10:03 ` Torsten Duwe
2016-03-09 10:13 ` Jiri Kosina
2016-03-09 11:16 ` Torsten Duwe [this message]
2016-03-09 12:56 ` Petr Mladek
2016-03-09 10:27 ` Michael Ellerman
2016-03-10 0:40 ` Balbir Singh
2016-03-15 10:25 ` Miroslav Benes
2016-03-17 15:42 ` Torsten Duwe
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