All of lore.kernel.org
 help / color / mirror / Atom feed
From: Seth Forshee <seth.forshee@canonical.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
	Nikolay Borisov <nborisov@suse.com>,
	x86@kernel.org, Masami Hiramatsu <masami.hiramatsu@gmail.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	bpf@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] x86: Disable CET instrumentation in the kernel
Date: Fri, 29 Jan 2021 11:58:47 -0600	[thread overview]
Message-ID: <YBRM181kNGBVKU4V@ubuntu-x1> (raw)
In-Reply-To: <20210129170755.GF27841@zn.tnic>

On Fri, Jan 29, 2021 at 06:07:55PM +0100, Borislav Petkov wrote:
> On Fri, Jan 29, 2021 at 11:03:31AM -0600, Josh Poimboeuf wrote:
> > On Fri, Jan 29, 2021 at 06:54:08PM +0200, Nikolay Borisov wrote:
> > > 
> > > 
> > > On 29.01.21 г. 18:49 ч., Josh Poimboeuf wrote:
> > > > Agreed, stable is a good idea.   I think Nikolay saw it with GCC 9.
> > > 
> > > 
> > > Yes I did, with the default Ubuntu compiler as well as the default gcc-10 compiler: 
> > > 
> > > # gcc -v -Q -O2 --help=target | grep protection
> > > 
> > > gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04) 
> > > COLLECT_GCC_OPTIONS='-v' '-Q' '-O2' '--help=target' '-mtune=generic' '-march=x86-64'
> > >  /usr/lib/gcc/x86_64-linux-gnu/9/cc1 -v -imultiarch x86_64-linux-gnu help-dummy -dumpbase help-dummy -mtune=generic -march=x86-64 -auxbase help-dummy -O2 -version --help=target -fasynchronous-unwind-tables -fstack-protector-strong -Wformat -Wformat-security -fstack-clash-protection -fcf-protection -o /tmp/ccSecttk.s
> > > GNU C17 (Ubuntu 9.3.0-17ubuntu1~20.04) version 9.3.0 (x86_64-linux-gnu)
> > > 	compiled by GNU C version 9.3.0, GMP version 6.2.0, MPFR version 4.0.2, MPC version 1.1.0, isl version isl-0.22.1-GMP
> > > 
> > > 
> > > It has -fcf-protection turned on by default it seems. 
> > 
> > Yup, explains why I didn't see it:
> > 
> > gcc version 10.2.1 20201125 (Red Hat 10.2.1-9) (GCC)
> > COLLECT_GCC_OPTIONS='-v' '-Q' '-O2' '--help=target' '-mtune=generic' '-march=x86-64'
> >  /usr/libexec/gcc/x86_64-redhat-linux/10/cc1 -v help-dummy -dumpbase help-dummy -mtune=generic -march=x86-64 -auxbase help-dummy -O2 -version --help=target -o /tmp/cclBz55H.s
> 
> The fact that you triggered it with an Ubuntu gcc explains why the
> original patch adding that switch:
> 
> 29be86d7f9cb ("kbuild: add -fcf-protection=none when using retpoline flags")
> 
> came from a Canonical.
> 
> Adding the author to Cc for FYI.
> 
> Seth, you can find this thread starting here:
> 
> https://lkml.kernel.org/r/20210128215219.6kct3h2eiustncws@treble

Thanks for the heads up. This still works fine for our needs.

Acked-by: Seth Forshee <seth.forshee@canonical.com>

  reply	other threads:[~2021-01-29 17:59 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-27 13:43 kprobes broken since 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()") Nikolay Borisov
2021-01-27 15:13 ` Masami Hiramatsu
2021-01-27 15:24   ` Masami Hiramatsu
2021-01-27 17:57     ` Nikolay Borisov
2021-01-28  1:34       ` Masami Hiramatsu
2021-01-28  3:38         ` Masami Hiramatsu
2021-01-28  7:11           ` Nikolay Borisov
2021-01-28 16:12           ` Nikolay Borisov
2021-01-28 16:45             ` Nikolay Borisov
2021-01-28 16:50               ` Josh Poimboeuf
2021-01-28 21:52                 ` [PATCH] x86: Disable CET instrumentation in the kernel Josh Poimboeuf
2021-01-29  6:23                   ` Nikolay Borisov
2021-01-29 10:21                   ` Borislav Petkov
     [not found]                     ` <20210129151034.iba4eaa2fuxsipqa@treble>
2021-01-29 16:30                       ` Borislav Petkov
2021-01-29 16:49                         ` Josh Poimboeuf
2021-01-29 16:54                           ` Nikolay Borisov
2021-01-29 17:03                             ` Josh Poimboeuf
2021-01-29 17:07                               ` Borislav Petkov
2021-01-29 17:58                                 ` Seth Forshee [this message]
2021-01-29 18:06                   ` [tip: x86/urgent] x86/build: " tip-bot2 for Josh Poimboeuf
2021-01-28 18:24               ` kprobes broken since 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()") Peter Zijlstra
2021-01-29  1:34                 ` Alexei Starovoitov
2021-01-29  6:36                   ` Nikolay Borisov
     [not found]                   ` <YBPNyRyrkzw2echi@hirez.programming.kicks-ass.net>
     [not found]                     ` <20210129224011.81bcdb3eba1227c414e69e1f@kernel.org>
     [not found]                       ` <20210129105952.74dc8464@gandalf.local.home>
2021-01-29 16:24                         ` Peter Zijlstra
2021-01-29 17:45                           ` Alexei Starovoitov
2021-01-29 17:59                             ` Peter Zijlstra
2021-01-29 19:01                               ` Steven Rostedt
2021-01-29 21:05                                 ` Alexei Starovoitov
2021-01-30  1:41                                   ` Masami Hiramatsu
2021-01-29 21:24                                 ` Steven Rostedt
2021-01-30  8:28                                   ` Peter Zijlstra
2021-01-30 12:44                                     ` Steven Rostedt
2021-02-02 10:45                                       ` Peter Zijlstra
2021-02-02 14:52                                         ` Steven Rostedt
2021-02-02 16:45                                           ` Peter Zijlstra
2021-02-02 16:56                                             ` Steven Rostedt
2021-02-02 18:30                                               ` Peter Zijlstra
2021-02-02 21:05                                                 ` Steven Rostedt
2021-02-03 13:33                                                   ` Masami Hiramatsu
2021-02-03 13:52                                                     ` Steven Rostedt
2021-01-30  2:02                               ` Masami Hiramatsu
2021-01-30  3:08                                 ` Alexei Starovoitov
2021-01-30 12:10                                   ` Masami Hiramatsu
2021-01-27 16:44   ` Peter Zijlstra

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=YBRM181kNGBVKU4V@ubuntu-x1 \
    --to=seth.forshee@canonical.com \
    --cc=ast@kernel.org \
    --cc=bp@alien8.de \
    --cc=bpf@vger.kernel.org \
    --cc=jpoimboe@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=masami.hiramatsu@gmail.com \
    --cc=mhiramat@kernel.org \
    --cc=nborisov@suse.com \
    --cc=peterz@infradead.org \
    --cc=rostedt@goodmis.org \
    --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 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.