From: "H. Peter Anvin" <hpa@zytor.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Richard Henderson <rth@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
David Daney <david.daney@cavium.com>,
Michael Ellerman <michael@ellerman.id.au>,
Jan Glauber <jang@linux.vnet.ibm.com>,
the arch/x86 maintainers <x86@kernel.org>,
Xen Devel <xen-devel@lists.xensource.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
peterz@infradead.org
Subject: Re: [PATCH][RFC] jump_labels/x86: Use either 5 byte or 2 byte jumps
Date: Fri, 07 Oct 2011 15:03:25 -0700 [thread overview]
Message-ID: <4E8F772D.20408@zytor.com> (raw)
In-Reply-To: <1318024853.4729.88.camel@gandalf.stny.rr.com>
On 10/07/2011 03:00 PM, Steven Rostedt wrote:
>
> Ouch, quite shaken by k.org? I guess I should have substituted go blind
> with being hacked.
>
Well, yes, but I would have said exactly the same thing before.
> The thing is, it may be as simple as an out of tree module screwing up
> the jump table. Or worse, gcc not doing things that we did not expect.
> If this is the case, jump labels can be disabled from modifying code.
>
> But if we just want to do the BUG() case, this will be a big hammer to
> the code and we just prevent any further progress until the issue is
> addressed. Which may be tell people to disable jump labels in their
> code, or use a different compiler.
That is EXACTLY what should happen. Something is wrong to the point of
the kernel is *known* to be executing the wrong code. That is an
extremely serious condition and should be treated as such.
If you want, you could have a debug option to demote this to WARN, but I
really don't want to see it by default.
-hpa
next prev parent reply other threads:[~2011-10-07 22:03 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-01 21:55 [PATCH RFC V2 0/5] jump-label: allow early jump_label_enable() Jeremy Fitzhardinge
2011-10-01 21:55 ` [PATCH RFC V2 1/5] jump_label: use proper atomic_t initializer Jeremy Fitzhardinge
2011-10-01 21:55 ` [PATCH RFC V2 2/5] stop_machine: make stop_machine safe and efficient to call early Jeremy Fitzhardinge
2011-10-02 0:36 ` Tejun Heo
2011-10-03 19:24 ` [Xen-devel] " Konrad Rzeszutek Wilk
2011-10-01 21:55 ` [PATCH RFC V2 3/5] jump_label: if a key has already been initialized, don't nop it out Jeremy Fitzhardinge
2011-10-03 15:02 ` Jason Baron
2011-10-03 15:47 ` Steven Rostedt
2011-10-03 16:27 ` Jeremy Fitzhardinge
2011-10-04 14:10 ` Jason Baron
2011-10-04 15:18 ` Jeremy Fitzhardinge
2011-10-04 16:30 ` H. Peter Anvin
2011-10-04 17:53 ` Jason Baron
2011-10-04 18:05 ` Steven Rostedt
2011-10-06 0:16 ` Jeremy Fitzhardinge
2011-10-06 0:17 ` H. Peter Anvin
2011-10-06 0:47 ` Jeremy Fitzhardinge
2011-10-06 17:53 ` Jeremy Fitzhardinge
2011-10-06 18:10 ` Jason Baron
2011-10-06 18:13 ` H. Peter Anvin
2011-10-06 21:39 ` Jeremy Fitzhardinge
2011-10-06 22:08 ` Steven Rostedt
2011-10-06 18:15 ` Jeremy Fitzhardinge
2011-10-06 18:33 ` Jason Baron
2011-10-06 18:35 ` H. Peter Anvin
2011-10-06 18:43 ` Jason Baron
2011-10-06 18:26 ` Steven Rostedt
2011-10-06 18:29 ` H. Peter Anvin
2011-10-06 18:38 ` Jason Baron
2011-10-06 19:34 ` Steven Rostedt
2011-10-06 20:33 ` Jason Baron
2011-10-06 20:45 ` Steven Rostedt
2011-10-06 18:50 ` Richard Henderson
2011-10-06 19:28 ` Steven Rostedt
2011-10-06 21:42 ` Jeremy Fitzhardinge
2011-10-06 22:06 ` Steven Rostedt
2011-10-06 22:10 ` Jeremy Fitzhardinge
2011-10-06 22:20 ` Steven Rostedt
2011-10-07 17:09 ` [PATCH][RFC] jump_labels/x86: Use either 5 byte or 2 byte jumps Steven Rostedt
2011-10-07 18:52 ` Jason Baron
2011-10-07 19:21 ` Steven Rostedt
2011-10-07 21:48 ` H. Peter Anvin
2011-10-07 22:00 ` Steven Rostedt
2011-10-07 22:03 ` H. Peter Anvin [this message]
2011-10-07 19:33 ` Steven Rostedt
2011-10-07 19:40 ` Jeremy Fitzhardinge
2011-10-07 19:58 ` Steven Rostedt
2011-10-07 20:04 ` Peter Zijlstra
2011-10-10 15:36 ` [PATCH RFC V2 3/5] jump_label: if a key has already been initialized, don't nop it out Jason Baron
2011-10-10 19:58 ` Jeremy Fitzhardinge
2011-10-10 20:10 ` Jason Baron
2011-10-01 21:55 ` [PATCH RFC V2 4/5] x86/jump_label: drop arch_jump_label_text_poke_early() Jeremy Fitzhardinge
2011-10-01 21:55 ` [PATCH RFC V2 5/5] sparc/jump_label: " Jeremy Fitzhardinge
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=4E8F772D.20408@zytor.com \
--to=hpa@zytor.com \
--cc=davem@davemloft.net \
--cc=david.daney@cavium.com \
--cc=jang@linux.vnet.ibm.com \
--cc=jbaron@redhat.com \
--cc=jeremy.fitzhardinge@citrix.com \
--cc=jeremy@goop.org \
--cc=linux-kernel@vger.kernel.org \
--cc=michael@ellerman.id.au \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=rth@redhat.com \
--cc=x86@kernel.org \
--cc=xen-devel@lists.xensource.com \
/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).